Infantile cataracts

SURVEY OF OPHTHALMOLOGY VOLUME40- NUMBER 6- MAY-JUNE 1996

MAJOR REVIEW

Infantile Cataracts S C O T T R. LAMBERT, MD, AND ARLENE V. DRACK, MD

Department of Ophthalmology, Emory University, Atlanta, Georgia, USA Cataracts are one of the most treatable causes of visual i m p a i r m e n t during infancy. Recent epidemiological studies have shown that they have a prevalence of 1.2 to 6.0 cases p e r 10,000 infants. The morphology of infantile cataracts can be helpful in establishing their etiology and prognosis. Early surgery and optical correction have resulted in an improved outcome for infants with either unilateral or bilateral cataracts. While contact lenses continue to be the standard means of optically correcting an infant's eyes after cataract surgery, intraocular lenses are gaining in popularity as an alternative means of optically correcting these eyes. Post-operative complications occur more commonly after infantile than adult cataract surgery and many of these complications do not develop until years later. As a result, it is critical that children be followed closely on a long term basis after infantile cataract surgery. (Surv Ophthalmol 40:427-458, 1996)

Abstract.

Key words: amblyopia • aphakic glaucoma • congenital cataracts • contact lenses infantile cataracts • intraocular lenses • nystagmus • secondary membranes • stereopsis

D u r i n g infancy, a c a t a r a c t n o t o n l y b l u r s t h e reti n a l i m a g e b u t also d i s r u p t s t h e d e v e l o p m e n t o f t h e visual p a t h w a y s in t h e c e n t r a l n e r v o u s system. T h i s review will f o c u s o n t h e p r e v a l e n c e , m o r p h o l ogy, etiology, w o r k - u p a n d m a n a g e m e n t o f cataracts d u r i n g t h e first 18 m o n t h s o f life. W h i l e m a n y o f t h e s e c a t a r a c t s a r e c o n g e n i t a l , in s o m e cases it c a n b e d i f f i c u l t to e s t a b l i s h t h e i r a g e o f o n s e t w i t h certainty. T h e r e f o r e , all c a t a r a c t s d e v e l o p i n g d u r i n g t h e first 18 m o n t h s o f life will b e r e f e r r e d to as i n f a n t i l e c a t a r a c t s .

noses, whereas the highest prevalence rates have b e e n r e p o r t e d in E u r o p e a n s t u d i e s s u r v e y i n g cohorts of older children. The Birth Defects Monitoring Program (BDMP) is a n a t i o n a l s u r v e i l l a n c e system in t h e U n i t e d States w h i c h m o n i t o r s h o s p i t a l d i s c h a r g e d a t a f o r b i r t h d e f e c t s a n d o t h e r c o n d i t i o n s o f t h e newb o r n . 6° T h e p r e v a l e n c e o f c a t a r a c t r e c o r d e d in n e o n a t a l d i s c h a r g e r e c o r d s f r o m 1988 to 1991 was 1.2 p e r 10,000 b i r t h s ( T a b l e 1). 119 T h e p r e v a l e n c e was h i g h e s t in t h e n o r t h e a s t e r n states a n d l o w e s t in t h e w e s t e r n a n d n o r t h - c e n t r a l states. T h e Metropolitan Atlanta Congenital Defects Program (MACDP) monitors the occurrence of congenital m a l f o r m a t i o n s in i n f a n t s o n e y e a r o f a g e o r less in the metropolitan Atlanta area by reviewing neon a t a l a n d p e d i a t r i c h o s p i t a l a d m i s s i o n r e c o r d s . 6° The prevalence of cataracts reported by MACDP b e t w e e n 1988 a n d 1991 was 1.4 p e r 10,000 b i r t h s a m o n g w h i t e s a n d 1.7 p e r 10,000 b i r t h s a m o n g n o n - w h i t e s ( T a b l e 2). In contrast, European population-based studies

I. P r e v a l e n c e The prevalence of infantile cataracts has been r e p o r t e d to b e as h i g h as 6 to as low as 1.2 cases p e r 10,000 b i r t h s . 135,251-253 W h i l e t h e s e d i f f e r e n c e s may partially reflect the ethnic and racial diversity o f t h e p o p u l a t i o n s s t u d i e d , t h e y also l i k e l y r e f l e c t different methodologies of ascertainment. The l o w e s t p r e v a l e n c e s h a v e b e e n r e p o r t e d in two p o p u l a t i o n - b a s e d s t u d i e s f r o m t h e U n i t e d States w h i c h have relied primarily on hospital discharge diag427

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Surv Ophthalmol 40 (6) May-June 1996 TABLE 1

TABLE 2

Prevalence of Congenital Cataracts in the United States (per 10,000 births) (Birth Defects Monitoring Program) 119

Prevalence of Congenital Cataracts by Race in Metropolitan Atlanta (per 10,000 births) (Metropolitan Atlanta Congenital Defects Program) 119

South West Northeast North Central Total U.S.A.

1988

1989

1990

1991

Total

0.4 1.2 1.7 0.8 1.0

2.0 1.1 2.0 1.5 1.5

2.3 0.7 1.5 0.8 1.1

0.8 1.1 1.6 1.1 1.1

1.3 1.1 1.7 1.0 1.2

have f o u n d a 3-5 times h i g h e r prevalence o f infantile cataracts. T h e Birth C o h o r t Study evaluated 97% o f all children b o r n in the U n i t e d K i n g d o m between April 5 a n d 11, 1970, w h e n they were 10 years o f age. 252 T h e assessment i n c l u d e d a determ i n a t i o n of best c o r r e c t e d m o n o c u l a r visual acuity a n d a review o f the medical records o f all children with k n o w n ocular p r o b l e m s or s u b n o r m a l visual acuity. O f the 12,853 children evaluated, f o u r h a d bilateral cataracts (3.3/10,000) a n d three h a d mon o c u l a r cataracts (2.3/10,000) for a c o m b i n e d prevalence rate o f 5.6/10,000. A l t h o u g h these cataracts were n o t all d i a g n o s e d d u r i n g infancy, it was a s s u m e d that all of these cataracts were p r e s e n t at birth. A second birth c o h o r t study was p e r f o r m e d on all children b o r n in 1984 in the O x f o r d s h i r e H e a l t h district in England. It was a s s u m e d that all o f these children were b e i n g treated for all o f their ocular p r o b l e m s within this health district. T h e prevalence of cataracts was t h e n ascertained by reviewing the medical records of all children in this health district b o r n in 1984 w h e n they were 2-5 years o f age. O u t of a birth c o h o r t o f 6687 child r e n , f o u r h a d c a t a r a c t s ( 6 / 1 0 , 0 0 0 b i r t h s ) . TM While the cataracts in two of these children were d i a g n o s e d d u r i n g infancy, the cataracts in the other two children were n o t as visually significant a n d were n o t d i a g n o s e d until these children were 2-5 years o f age. A similar study was also p e r f o r m e d in Sweden, w h e r e o n e out o f 2447 four-year-olds ( 4 / 10,000) s c r e e n e d h a d a cataract335 In France, the prevalence o f infantile cataracts has b e e n r e p o r t e d to be 2.2 cases p e r 10,000 children. 25a T h e E u r o p e a n studies p r o b a b l y provide a closer a p p r o x i m a t i o n o f the true prevalence of visually significant cataracts d u r i n g early c h i l d h o o d t h a n the A m e r i c a n studies, b u t they are flawed by their reliance o n medical records r a t h e r t h a n biomicroscopy. It is likely that m a n y visually insignificant cataracts were missed by this m e t h o d of ascertainm e n t . In addition, s o m e of the cataracts m a y have b e e n e r r o n e o u s l y a s s u m e d to have b e e n infantile cataracts, w h e n in fact they m a y have b e e n acq u i r e d later in childhood. T h e m e t h o d o l o g i e s used by the A m e r i c a n studies are flawed by their

White Non-white

1988

1989

1990

1991

Total

0.9 0.7

1.4 2.5

1.8 1.2

1.4 2.3

1.4 1.7

reliance on hospital discharge summaries. Since m o s t infantile cataracts are n o t d i a g n o s e d d u r i n g the n e o n a t a l period, these studies likely underestimated the true prevalence of infantile cataracts. II. M o r p h o l o g y A. EMBRYOLOGY U n d e r s t a n d i n g the e m b r y o l o g y o f the lens can be helpful in classifying infantile cataracts. T h e lens f o r m s f r o m surface e c t o d e r m a l cells overlying the optic vesicle. B e g i n n i n g on the 28th day of gestation, this single layer of e c t o d e r m a l cells thickens a n d b e c o m e s the lens placode. 291 O n the 33rd day of gestation the lens p l a c o d e invaginates to f o r m the lens c u p ? 98 W h e n the lens cup separates f r o m the overlying e c t o d e r m it is r e f e r r e d to as the lens vesicle. 24° T h e lens vesicle initially consists of a single layer of epithelial cells covered by a basal lamina. T h e basal l a m i n a t h e n thickens to b e c o m e the lens capsule. O n the 45th day of gestation the cells in the p o s t e r i o r h a l f of the lens vesicle elongate anteriorly to fill its lumen24° T h e s e fibers are ref e r r e d to as the p r i m a r y lens fibers. T h e epithelial cells o n the a n t e r i o r surface of the lens vesicle t h e n migrate laterally to the equatorial region a n d f o r m the lens bow. D u r i n g the third gestational m o n t h the cells in the bow region f o r m s e c o n d a r y lens fibers which elongate until they encapsulate the p r i m a r y lens fibers. T h e interface at which they m e e t f o r m s the lens sutures. T h e a n t e r i o r lens suture has an u p r i g h t Y-configuration while the posterior suture has an inverted Y-configuration. T h e i n n e r m o s t core of the lens f o r m e d by the p r i m a r y lens fibers is r e f e r r e d to as the e m b r y o n i c nucleus while the s u r r o u n d i n g sutural zone is r e f e r r e d to as the fetal nucleus. As additional s e c o n d a r y lens fibers are a d d e d to the lens, it develops an ellipsoid shape. 2s T h e r e m o v a l o f the lens d u r i n g e m b r y o genesis results in flattening of the cornea, an arrest in the d e v e l o p m e n t of the vitreous h u m o r a n d a r e t a r d a t i o n of axial elongation. 47 I f the lens is k e p t intact a n d viable, these effects can be reversed by r e i m p l a n t i n g the lens. B. MORPHOLOGIC TYPES Infantile cataracts are usually subdivided on the basis of their m o r p h o l o g y (Table 3). While in m o s t

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429

TABLE 3

Morphological Types of Congenital Cataracts 1. Zonular A. Nuclear B. Lamellar C. Sutural D. Capsular 2. Polar A. Anterior B. Posterior 1. Posterior lentiglobus 3. Total 4. Membranous 5. Persistent hyperplastic primary vitreous

Fig. 1. A dense nuclear cataract with a prominent Y suture visible on the anterior surface of the lens in a threeweek-old infant with bilateral cataracts.

cases this m e t h o d of classification is helpful in suggesting an etiology, it occasionally can be misleading since there can be great variability in the morp h o l o g y of cataracts even within the same pedigree. s°,229 T h e m o r p h o l o g i c a l a p p e a r a n c e o f cataracts can also be helpful in predicting the visual prognosis .200-201

are m o r e c o m m o n than posterior capsular opacities in infants. Frequently the iris will be a d h e r e n t to an anterior capsular cataract, preventing the pupil f r o m dilating in the affected q u a d r a n t (Fig. 5). A n t e r i o r capsular opacities are usually visually insignificant.

1. Zonular Cataracts

2. Polar Cataracts

T h e most c o m m o n type o f infantile cataract is a zonular cataract which is characterized by the opacification o f a discrete region o f the lens? °3 A nuclear cataract refers to opacification of the central zone o f the lens, specifically the region between the anterior a n d posterior Y sutures (Fig. 1). Nuclear cataracts are usually 3-4 m m in size, a n d often have opacified cortical fibers encircling the nuclear opacity, which are r e f e r r e d to as riders (Fig. 2). T h e y are bilateral in two-thirds o f affected patients a n d are c o m m o n l y a s s o c i a t e d with mic r o p h t h a l m o s a n d m i c r o c o r n e a . 12~ T h e density of nuclear cataracts can vary greatly. Lamellar cataracts are characterized by a lamella o f lenticular opacification sandwiched between a clear nucleus a n d cortex. T h e y o c c u r s e c o n d a r y to a transient insult to the lens d u r i n g its development. They are usually bilateral, but frequently an interocular difference in the degree of lenticular opacification is present. This difference may lead to amblyopia. T h e r e can also be a difference in the degree o f opacification between different meridians (Fig. 3). Sutural cataracts are opacities o f the lens sutures. They can be associated with nuclear cataracts (Fig. 4), b u t w h e n they o c c u r as an isolated finding they seldom impair vision. Isolated sutural cataracts are often first n o t e d as an incidental finding d u r i n g a routine ocular examination. Capsular cataracts are lens opacities which involve either the anterior or posterior lens capsule, sparing the lens cortex. Anterior capsular opacities

Polar cataracts are opacities of the subcapsular cortex in the polar regions of the lens. A n t e r i o r polar cataracts are typically 0.5-2 m m in diameter a n d are usually visually insignificant (Fig. 6). Ninety p e r c e n t of anterior polar cataracts are unilateral. W h e n bilateral, they are c o m m o n l y asymmetrical. n6 T h e y do n o t usually progress over time. 193 Because polar cataracts are readily visible without special instrumentation, they are frequently diagn o s e d soon after birth by a p a r e n t or p r i m a r y care physician. Patients with bilateral anterior polar cataracts n e e d to be followed closely because of their increased risk of developing amblyopia, n6 Posterior polar cataracts are usually small a n d

Fig. 2. A nuclear cataract with cortical riders (arrow). The fellow eye had a similar appearing cataract.

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Fig. 3.

Left: A lamellar Cataract with a clear central zone and asymmetrical opacification of the different sectors of the lens. The visual acuity was 20/40 in this eye. The fellow eye had a denser cataract and counting fingers vision. Right: Slit-lamp photograph of the same eye using retroillumination.

are s e l d o m d i a g n o s e d without o p h t h a l m o l o s c o p y or biomicroscopy. Because o f their close proximity to the macula, even a small p o s t e r i o r p o l a r cataract can i m p a i r vision. T h e y are c o m m o n l y p r e s e n t in children with aniridia (Fig. 7).192 A distinctive type o f p o s t e r i o r p o l a r cataract is r e f e r r e d to as a p o s t e r i o r lentiglobus or lenticonus. While p o s t e r i o r lentiglobus cataracts are usually 15 m m in size a n d c e n t e r e d o n the p o s t e r i o r pole o f the lens (Fig. 8), they can also be e c c e n t r i c Y In 90% o f cases, p o s t e r i o r lentiglobus cataracts are unilateral. While s o m e are p r e s e n t at birth, m a n y develop later in childhood. 5° H i g h myopia, d u e to the increased a n t e r o - p o s t e r i o r d i a m e t e r of the

lens, m a y p r e c e d e opacification. Several theories have b e e n a d v a n c e d to explain their genesis. T h e m o s t widely a c c e p t e d t h e o r y is that they f o r m because of a congenital weakness o f the p o s t e r i o r lens capsule. 123 Intralenticular pressure t h e n causes the p o s t e r i o r cortical lamellae to prolapse t h r o u g h this capsular defect. T h e p r o l a p s e d lamellae t h e n opacify (Fig. 9). It has also b e e n postulated that a defect develops in the p o s t e r i o r lens capsule seco n d a r y to traction c r e a t e d by a persistent hyaloid vessel. While a hyaloid vessel m a y occasionally b e seen a t t a c h e d to the p o s t e r i o r lens capsule underlying the lentiglobus, this is an inconsistent finding. 133

Fig. 4. Left: An autosomal dominantly inherited sutural cataract associated with mild nuclear opacification. Right: The fellow eye with a nearly identical appearing cataract.

INFANTILE CATARACTS

431

Fig. 5. An anterior capsular cataract with iris adherent

Fig. 6. A small unilateral anterior polar cataract (arrow)

to the cataract.

in an eye with 20/20 visual acuity.

3. Total Cataracts

m i c r o p h t h a l m o s a n d the congenital rubella syndrome. TM

Total cataracts may develop in infants. In some cases they can be observed to f o r m f r o m partial cataracts, while in o t h e r cases the lens is completely opacified w h e n the cataract is first diagnosed (Fig. 10). T h e y are frequently bilateral a n d often begin as lamellar or nuclear cataracts.

4. Membranous Cataracts M e m b r a n o u s cataracts f o r m w h e n the lens cortex a n d nucleus are partially or completely reabsorbed, leaving b e h i n d a small a m o u n t o f opacified lens material sandwiched between the anterior a n d posterior lens capsules. T h e y are the most comm o n type o f cataracts associated with Lowe synd r o m e a n d H a l l e r m a n n - S t r e i f f - F r a n ~ o i s synd r o m e . 69,243 T h e y can also o c c u r in association with

5. Persistent Hyperplastic Primary Vitreous Persistent hyperplastic p r i m a r y vitreous (PHPV) is usually a unilateral ocular condition associated with a r e t r o l e n t i c u l a r f i b r o v a s c u l a r m e m brane. 12y,2°8A l t h o u g h the lenses in most eyes with PHPV are initially clear, they usually 0pacify over time. 215 Even w h e n the lens remains clear, the ret r o l e n t i c u l a r m e m b r a n e is u s u a l l y s u f f i c i e n t l y o p a q u e to obstruct the visual axis. T h e lens may also be p u s h e d forward by the retrolenticular m e m b r a n e , causing the anterior c h a m b e r to bec o m e shallow. Eyes with PHPV usually have rubeosis iridis. 99 Many also develop glaucoma. Most also have the ciliary processes pulled centrally by the

Fig. 7. Left: A posterior polar cataract in an infant with autosomal dominantly inherited aniridia. Right: The same eye six years later. The cataract is now larger and denser. The visual acuity is counting fingers at 10 feet in this eye and 20/400 in the fellow eye, which has a clear lens.

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Fig. 9. Posterior lentiglobus with overlying lenticular opacification. The visual acuity was reduced to 20/400 in this eye.

Fig. 8. Posterior lentiglobus with overlying vacuoles and 20/40 visual acuity. There has been no progression of the lenficular changes during a four-year follow-up.

retrolenticular m e m b r a n e . A fibrovascular proliferation may also o c c u r in the peripapillary region, leading to a tractional retinal d e t a c h m e n t . Twothirds o f eyes with PHPV are m i c r o p h t h a l m i c ? 9 While most eyes with PHPV have a p o o r prognosis, the degree o f extralenticular involvement is variable a n d some eyes with PHPV behave similarly to eyes with an isolated posterior polar cataract.

III. E t i o l o g y T h e etiology of infantile cataracts can be established in up to one-half of children with bilateral cataracts, but in a smaller p r o p o r t i o n o f infants with unilateral cataracts. 2,75,~73 Infantile cataracts most c o m m o n l y o c c u r s e c o n d a r y to genetic or metabolic diseases, intrauterine infections or trauma; less c o m m o n l y they may o c c u r as a side effect of t r e a t m e n t with certain medications or radiation therapy (Table 4).

are m o r e c o m m o n l y inherited as autosomal recessive traits. 14,~54 In Egypt where one-third of all marriages are c o n s a n g u i n e o u s , M o s t a f a a n d coll e a g u e s 188 r e p o r t e d a u t o s o m a l recessive i n h e r i tance for six of seven pedigrees with inherited infantile cataracts. Linkage analysis has b e e n used to d e t e r m i n e the genetic loci o f certain autosomal d o m i n a n t cataracts (Table 5). Coppock-like cataract has b e e n linked to the g a m m a E-crystallin gene on c h r o m o s o m e 2,16° C o p p o c k cataract to c h r o m o s o m e lq21-q25, 55,217 M a r n e r cataract to 16q22, 62 a n d cerulean cataract to 17q24. s T h e Cerulean cataract links closely to the galactokinase gene, but galactokinase levels in these patients are normal.

B. METABOLIC T h e most c o m m o n metabolic disturbance causing cataracts d u r i n g infancy is galactosemia. Galac-

A. GENETIC Infantile cataracts may be inherited as autosomal d o m i n a n t , autosomal recessive or X-linked recessive traits. Autosomal d o m i n a n t cataracts are most c o m m o n l y bilateral nuclear opacities, but m a r k e d variability can be present even within the same pedigree329 In an e x t e n d e d pedigree of 28 patients with autosomal d o m i n a n t nuclear cataracts, Scott et al 2~ r e p o r t e d that 19 of the affected family m e m b e r s h a d unilateral cataracts while nine h a d bilateral cataracts. Less commonly, anterior polar, posterior polar, a n d posterior lentiglobus cataracts can be autosomal d o m i n a n t l y inherited. 8°,186,229,263 In the U n i t e d States, infantile cataracts are most commonly inherited as autosomal d o m i n a n t traits; 116 however, in countries where there is a high prevalence o f parental consanguinity, infantile cataracts

Fig. 10. Total cataract in a two-month-old infant delivered three months premature with bilateral cataracts. The tunica vasculosa lends may be seen encircling the lens. The child was found to have threshold retinopathy of prematurity in both eyes after cataract extraction.

INFANTILE CATARACTS

433 TABLE 4

Etiology of Cataracts During Infancy Inherited with systemic abnormalities (continued)

Idiopathic Intrauterine infection

Craniofacial syndromes Cerebro-oculo-facio-skeletal syndrome (COFS) 11~ Mitochondrial abnormalities Complex I deficiency 4°a Renal disease Lowe syndrome 265 Hallermann-Streiff-Frangois syndrome 243 Skeletal disease Smith-Lemli-Opitz44 Conradi syndrome ~53 Weill-Marchesani syndrome 122

Rubella 46 Varicella45,141 Toxoplasmosis 246 Herpes simplex TM

Drug induced Corticosteroids 27

Metabolic disorders Galactosemia 247 Galactokinase deficiency 249 Hypocalcemia Hypoglycemia t72 Mannosidosis 152

Syndactyly, polydactyly or digital abnormalities Bardet-Biedl syndrome 95 Rubenstein-Taybi syndrome 226

Trauma Accidental Non-accidental

Central nervous system abnormalities Zellweger syndrome 187 Meckel-Gruber syndrome 162 Marinesco-SjiSgren syndrome 29° Infantile neuronal ceroid-lipofuscinosis (Batten's disease) 16

Miscellaneous Radiation Laser photocoagulation 32,3s

Other ocular diseases Microphthalmia 287 Aniridia 192 PHPV 99 Prematurity ~69 Peter's anomaly 286A Corneal guttata 263 Endophthalmitis 41

Cardiac disease Hypertropic cardiomyopathy 5~ Dermatological Crystalline cataract and uncombable hair 54 Cockayne syndrome 264 Rothmund-Thomson 273 Atopic dermatitis 48 Incontinentia pigment? 34 Progeria TM Ichthyosis 121 Ectodermal dysplasia 165

Inherited without systemic abnormalities Autosomal dominant 235 Autosomal recessive 72 X-linked 154

Inherited with systemic abnormalities Chromosomal abnormalities Trisomy2 134 Turner syndrome I5~ Trisomy 13 4 Trisomy 18 ~89 Translocation 3;4 2~6 Cri du chat syndrome TM Translocation 2; 14 ~86

Dental Anomalies Nance-Horan syndrome 154 Lenz syndrome 262

TABLE 5

Genetic Location of Inherited Cataracts Type

Chromosome/ Locus

Gene

Coppock (Zonular pulverulent)

1q21-q25

unknown

Coppock-like Marner Posterior polar Cerulean Nance-Horan (cataract + microcornea)

2q33-q36 16q22.1 16q22.1 17q24 Xp22.2-p22.3

gamma E-crystallin unknown unknown (near haptoglobin) unknown unknown

Authors Renwick et al 2J7 Donahue et aP 5 Lubsen et a116° Eiberg et a162 Maumenee et a1166 Armitage et al 8 Zhu et a1289 Stambolian et a1248 Lewis et a1154

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tosemia may be caused by a transferase, galactok i n a s e o r e p i m e r a s e deficiency. 247 G a l a c t o s e - 1 p h o s p h a t e uridyl transferase (GALT) deficiency occurs in 1:40,000 n e w b o r n s in the U n i t e d States a n d 1:23,000 n e w b o r n s in I r e l a n d ? 7,65 A h o m o z y g o u s m u t a t i o n of Q188R on e x o n 6 of the GALT g e n e o n c h r o m o s o m e 9 13p is f o u n d in two-thirds o f children with the transferase deficiency. 64a5° This results in the a c c u m u l a t i o n o f galactose-l-phosp h a t e in the blood. Galactose is t h e n c o n v e r t e d to galactitol in the crystalline lens, resulting in an influx of water into the lens by osmosis. T h e hydration o f the lens t h e n disrupts the n o r m a l packing o f the lens fibers, resulting in a loss o f transparency. Early on, these lens changes have the app e a r a n c e of an oil-droplet in the c e n t e r o f the lens. T h e s e changes are initially reversible with the elimination of galactose f r o m the diet. 3° If left untreated, a lamellar cataract develops which m a y t h e n progress to a total cataract. In addition to cataracts, these children have failure-to-thrive as infants, which m a y lead to d e a t h if milk a n d milk p r o d u c t s are n o t e l i m i n a t e d f r o m their diet. Later in childh o o d , these children m a y have delayed developm e n t , a b n o r m a l speech, growth delay, ovarian failure a n d ataxia. 64 While eliminating galactose f r o m the diet can p r e v e n t the life-threatening p r o b l e m s which o c c u r d u r i n g infancy, dietary c o m p l i a n c e does n o t always correlate closely with the f o r m a tion o f cataracts in later c h i l d h o o d or with the associated abnormalities of late childhood. 17,3°,64 T h e N314D m u t a t i o n of the GALT g e n e causes the m i l d e r Duarte f o r m of galactosemia. C o m b i n a t i o n s o f Q188R, N314D a n d u n k n o w n m u t a t i o n s m a y result in phenotypically different f o r m s of galactosemia. 65 Galactokinase deficiency may cause cataracts with few or no systemic abnormalities. T h e galactokinase g e n e is o n c h r o m o s o m e 17 a n d has recently b e e n c l o n e d a n d f o u n d to h a r b o r homozygous m u t a t i o n s in s o m e patients with cataracts. 249 Heterozygotes for galactokinase deficiency have half n o r m a l values on b l o o d tests. Conflicting resuits have b e e n r e p o r t e d in the literature as to w h e t h e r partial loss o f e n z y m e activity leads to presenile cataracts. A l p h a mannosidosis can also b e associated with early onset cataracts. 152 L a m e l l a r cataracts may also develop in children with n e o n a t a l hypoglycemia or hypocalcemia. Neonatal hypoglycemia is m o r e c o m m o n in low birth weight infants. 172 C. I N F E C T I O U S

T h e congenital rubella s y n d r o m e (Fig. 11) was o n e of the m o s t c o m m o n cause of congenital cataracts in the U n i t e d States until the widespread us-

LAMBERT, DRACK

Fig. 11. A dense nuclear cataract in an infant born in England in 1988 with the congenital rubella syndrome (courtesy of David Taylor).

age o f the rubella vaccine. 46 D u r i n g the rubella epidemic in the U n i t e d States d u r i n g 1963-64, 16% of all children with the congenital rubella synd r o m e d e v e l o p e d cataracts. TM T h e congenital rubella s y n d r o m e is n o w rare in the U n i t e d States, b u t still occurs with s o m e f r e q u e n c y in o t h e r parts of the world. 42 Infantile cataracts also o c c u r occasionally in children after i n t r a u t e r i n e varicella, toxoplasmosis a n d h e r p e s simplex infections, 45,14~ or after bacterial or fungal endophthalmitis. Clinch a n d coworkers 4~ r e p o r t e d a 6-month-old infant with a partial cataract which rapidly progressed to a total cataract f r o m which c a n d i d a albicans was cultured. Cataracts m a y also develop after a varicella infection d u r i n g early c h i l d h o o d 2 m D. S Y N D R O M I C

Infantile onset cataracts o c c u r with a n u m b e r o f syndromes (Table 4). T h e y are a nearly universal finding with Lowe 4° a n d Hallermann-Streiff-Franyois syndromes, 69 b u t o c c u r less frequently in association with o t h e r s y n d r o m e s such as Trisomy 21.88 E. P R E M A T U R I T Y

T r a n s i e n t cataracts o c c u r occasionally in prem a t u r e infants, a,a69 T h e y are usually bilateral a n d b e g i n as clear vacuoles a l o n g the apices o f the posterior lens suture. T h e y m a y progress to p o s t e r i o r subcapsular vacuoles. In m o s t cases, they clear c o m p l e t e l y over the course o f several m o n t h s . All of the p r e m a t u r e infants with transient cataracts r e p o r t e d by Alden a n d coworkers 1 were septic a n d h a d b e e n treated with Kanamycin; 80% o f these infants also h a d an u n e x p l a i n e d m e t a b o l i c acidosis. 1 T h e s e authors suggested that osmotic changes in the lens of these infants m a y have caused these cataracts.

I N F A N T I L E CATARACTS

Fig. 12. A total cataract in a fiive-month-old-infant following diode laser treatment. The child was diagnosed as having Zone I threshold retinopathy of prematurity in both eyes at two months of age and subsequently had the avascular retina ablated bilaterally using a diode laser. The neovascularization of the retina regressed in both eyes, but three months later a total cataract developed in the right eye. The lens remained clear in the left eye.

E TRAUMA While t r a u m a is n o t a c o m m o n cause of cataracts d u r i n g infancy it should be considered, particularly w h e n a cataract is associated with o t h e r ocular signs suggestive o f a traumatic injury. The t r a u m a can be either b l u n t or penetrating. N o n a c c i d e n t a l causes for the t r a u m a must always be considered. Eyes with suspected traumatic cataracts should also be e x a m i n e d carefully for b o t h retinal a n d optic nerve injuries. G. LASER P H O T O C O A G U L A T I O N

Laser p h o t o c o a g u l a t i o n has b e e n used in r e c e n t years to ablate the avascular retina o f infants with threshold r e t i n o p a t h y o f prematurity. While the rate o f retinal d e t a c h m e n t appears to be as low if n o t lower after p h o t o a b l a t i o n o f the avascular retina c o m p a r e d to cryoablation, 39 laser photoablation can result in the f o r m a t i o n o f a cataract. Laseri n d u c e d cataracts are transient in some instances, but progress in some cases to total opacification o f the lens. 56 Christiansen a n d coworkers 38 r e p o r t e d total cataracts in six eyes following a r g o n laser p h o t o a b l a t i o n o f the avascular retina in f o u r infants with threshold r e t i n o p a t h y o f prematurity. All o f these eyes were also n o t e d to have a p r o m i n e n t anterior tunica vasculosa lentis a n d each eye developed a h y p h e m a after laser p h o t o c o a g u l a t i o n . O n e additional infant developed transient anterior

435

Fig. I3.

A dense posterior subcapsular cataract with some cortical opacification in a child treated with external beam radiation for bilateral retinoblastomas.

capsular a n d subcapsular opacities. They p r o p o s e d that the vasculature o n the anterior lens surface absorbed the laser e n e r g y causing a thermal injury to the lens, a n d advised against using A r g o n laser p h o t o a b l a t i o n in eyes with a p r o m i n e n t tunica vasculosa lentis because of the absorption s p e c t r u m o f an a r g o n laser. T h e y suggested that the risk of cataractogenesis may be lower using a diode laser. Howevel, clear cavitary lesions o f the lens also have b e e n n o t e d to develop after diode laser photo= coagulation 32 a n d we have n o t e d the d e v e l o p m e n t o f total cataracts in several infants following diode laser p h o t o c o a g u l a t i o n (Fig. 12). H. R A D I A T I O N - I N D U C E D

Radiation used to treat ocular a n d periocular tumors may i n d u c e cataracts in children (Fig. 13). A radiation dose of 15 Gy has b e e n shown to be associated with a 50% risk o f cataract formation, a°l Radiation usually causes posterior subcapsular cataracts, which typically have their onset 1-2 years after the c o m p l e t i o n o f radiation therapy. I. M E D I C A T I O N S

Systemic corticosteroids cause cataracts in u p to 15% o f children once a cumulative dose o f 1000 nag o f p r e d n i s o n e or the equivalent has b e e n reached. ~9 These cataracts usually begin as central posterior subcapsular opacities, but may progress to involve the entire lens? 29 J. I D I O P A T H I C

In most series, at least 50% o f bilateral infantile cataracts are idiopathic, n° T h e p e r c e n t a g e o f id-

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iopathic unilateral infantile cataracts is even higher.

IV. Work-up A. OCULAR EXAMINATION T h e work-up o f an infant with a unilateral or bilateral cataract should be tailored to the child. First, a careful history should be t a k e n to determ i n e if there were any p r o b l e m s d u r i n g the pregnancy, such as a rash or febrile illness, that m i g h t be suggestive o f an i n t r a u t e r i n e infection. An assessment of the child's general health should be elicited. T h e parents should also be asked if there are any relatives with congenital cataracts or decreased vision since childhood. An ocular examination should t h e n be p e r f o r m e d including an assessment o f visual acuity a n d the pupillary response. O c u l a r motility should also b e assessed, since it can be helpful in establishing the age o f onset of the cataracts? 3s,zs2 Biomicroscopy should be p e r f o r m e d . T h e pupils should be dilated to allow for a m o r e careful assessment o f the lenses a n d the fundi. In s o m e cases, sedation m a y be necessary to a d e q u a t e l y e x a m i n e the lenses o f an uncooperative infant. I f the cataract is too dense to allow the f u n d u s to be viewed, B-scan ultrasonog r a p h y should be p e r f o r m e d . A-scan ultrasonog r a p h y can also be helpful, particularly w h e n the age of onset o f a cataract is u n k n o w n . A s h o r t e r or l o n g e r axial length in the eye with the cataract is very suggestive of a congenital origin for the cataract? 38 It can also b e helpful to review the red reflexes in old p h o t o g r a p h s to try to date the onset of the cataract. Biomicroscopy should also b e perf o r m e d on b o t h parents a n d all siblings, since occasionally relatives are unaware o f incipient cataracts (Fig. 14). 40 B. LABORATORY STUDIES

Unless t h e r e is a definite h e r e d i t a r y basis for the cataracts, the work-up o f m o s t infants with bilateral cataracts should include: a fasting b l o o d sugar; p l a s m a calcium a n d p h o s p h o r u s ; an assay for u r i n e r e d u c i n g substances after a milk feeding; r e d b l o o d cell transferase a n d galactokinase levels; a n d T O R C H titers (toxoplasmosis, rubella, cytomegalovirus, a n d h e r p e s simplex). I f there is a history of a m a t e r n a l rash d u r i n g the pregnancy, varicella zoster a n t i b o d y titers should also be assayed. I f Lowe s y n d r o m e is suspected, the urine should be s c r e e n e d for a m i n o acids. In m o s t cases, l a b o r a t o r y investigations are n o t indicated for infants with unilateral cataracts. C. PEDIATRIC EVALUATION

Infants with bilateral cataracts should also be exa m i n e d by a pediatrician for systemic diseases a n d

LAMBERT, DRACK d y s m o r p h i c features. 2°5 An evaluation by a geneticist is a p p r o p r i a t e in s o m e cases. A t h o r o u g h evaluation by a pediatrician is particularly i m p o r t a n t for children with cataracts s e c o n d a r y to intrauterine infections, since they have a h i g h e r incidence of systemic a n d d e v e l o p m e n t a l anomalies, s9,141

V. Management Until the 1970s, e x t r e m e conservatism was advocated in the m a n a g e m e n t o f infantile cataracts. Pupillary dilation with a t r o p i n e or h o m a t r o p i n e was r e c o m m e n d e d to allow the infant to l o o k a r o u n d the cataract. If this p r o v e d inadequate, an optical iridectomy was t h e n r e c o m m e n d e d . 43 However, w h e n it was r e c o g n i z e d that optical iridectomies s e l d o m i m p r o v e d tile visual acuity of eyes with infantile cataracts a n d that the paralysis o f accomm o d a t i o n i n d u c e d by a t r o p i n e nullified any visual i m p r o v e m e n t that m i g h t result f r o m the i n d u c e d mydriasis, interest in the surgical removal of infantile cataracts increased 49 A. I N D I C A T I O N F O R S U R G E R Y

Cataract extraction is n o w the p r e f e r r e d treatm e n t o f m o s t visually significant infantile cataracts. Since a subjective visual acuity c a n n o t be o b t a i n e d in infants with cataracts, g r e a t e r reliance m u s t be placed on the m o r p h o l o g y of the cataract, o t h e r associated ocular findings, a n d the visual b e h a v i o r of the child, in o r d e r to ascertain w h e t h e r or n o t the cataract is visually significant. 1°9 While forced choice p r e f e r e n t i a l looking or visual evoked potentials can provide helpful i n f o r m a t i o n in the evaluation o f an infant with cataracts, they should n o t be relied o n exclusively, since they can also give s p u r i o u s results. 137,157,168,17°,258

T h e d e g r e e of visual i m p a i r m e n t i n d u c e d by a lens opacity differs m a r k e d l y d e p e n d i n g o n the location of the opacity. Generally, the m o r e p o s t e r i o r a n d central the location o f an opacity, the m o r e visually significant the opacity will be. While a 2 m m opacity o n the a n t e r i o r lens capsule m a y be associated with only a relatively m i n o r r e d u c t i o n in visual acuity, the s a m e sized opacity o n the posterior pole o f the lens can result in p r o f o u n d visual i m p a i r m e n t . Similarly, n u c l e a r cataracts, which are generally d e n s e r centrally, d e g r a d e vision m o r e t h a n lamellar cataracts, which are less d e n s e centrally. S o m e authors have r e c o m m e n d e d that all central lens opacities 3 m m or g r e a t e r in size should be r e m o v e d ; 283 however, F r e e m a n 76 has cautioned that s o m e children with large central lens opacities can have n o r m a l visual acuity. H e stressed the i m p o r t a n c e o f evaluating the visual f u n c t i o n o f o t h e r m e m b e r s o f the family to assess the effect o f their cataracts o n their visual acuity. While m a n y infantile cataracts are static, s o m e will progress a n d

INFANTILE CATARACTS

437

Fig. 14. Autosomally dominantly inherited anterior polar cataract in a mother (right eye, A,; left eye, B [arrow], E) and her daughter (right eye, C; left eye, D;). The cataracts are very asymmetrical in the mother, but quite symmetrical in her daughter. The cataract in the mother's left eye can be seen better with retroillumination (E).

others will clear over t i m e . ms Nuclear cataracts frequently b e c o m e progressively opaque, while sutural cataracts may dissipate, m In children with bilateral cataracts, it can also be difficult to predict in which eye the cataract is m o r e visually significant. While m o r e c o m m o n l y the larger opacity will be m o r e visually significant, Crawford 49 n o t e d that in seven o f 17 patients with bilateral, but asymmetrical lamellar cataracts, the eye with the larger lens opacity h a d better visual acuity. O n e patient could see only 2 0 / 4 0 0 in an eye with a 4.3 m m opacity while the fellow eye with a 5.1 m m opacity could see 20/60. W h e n a cataract is d i a g n o s e d after the n e o n a t a l period, it may be difficult to d e t e r m i n e w h e t h e r it is congenital or acquired. K u s h n e r 138 r e p o r t e d 2 0 /

80 or better visual acuity after cataract surgery in 14 o f 17 eyes with unilateral cataracts of u n k n o w n d u r a t i o n with n o r m a l corneal diameters a n d axial lengths; however, eight eyes with unilateral cataracts a n d m i c r o p h t h a l m o s h a d a p o o r visual outcome. Strabismus is also frequently an indicator of a l o n g s t a n d i n g unilateral cataract, a38,98z T h e morp h o l o g y o f the cataract can also be helpful in det e r m i n i n g if a cataract is congenital, since certain types o f cataracts (e.g., nuclear cataracts) are m o r e likely to be congenital than o t h e r types (e.g., lamellar a n d posterior lentiglobus cataracts, Fig 15). Nystagmus is also usually an indicator that visually significant cataracts have b e e n p r e s e n t for at least several months. If the cataracts are n o t d e e m e d to be visually

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Fig. 15. A small nuclear opacity in the left eye in a fiveyear-old child who failed a vision screening test for kindergarten. The visual acuity was counting fingers at ten feet in this eye and 20/20 in the fellow eye. No improvement in visual acuity occurred after cataract surgery and IOL implantation in this eye and occlusion therapy of the fellow eye.

significant, observation alone is appropriate. It is i m p o r t a n t to carefully follow these children to ensure that the cataracts do n o t progress a n d to m o n itor for refractive errors which c o u l d result in amblyopia. 24 Occasionally, c h r o n i c pupillary dilation with a mydriatic a g e n t such as 2.5% p h e n y l e p h r i n e will improve the visual function of an infantile eye with a partial cataract. Occlusion therapy alone may be the most appropriate therapy for certain unilateral partial cataracts if amblyopia is responsible for most o f the visual degradation. If an eye c a n n o t be rehabilitated nonsurgically, a cataract extraction should be p e r f o r m e d . B. S U R G E R Y

T h e timing a n d techniques for removing cataracts in infants has c h a n g e d considerably over the past two decades. As recently as the 1970s, it was r e c o m m e n d e d that surgery be d e f e r r e d until an infant was 3-6 m o n t h s of age. 23<269 It is now generally accepted that visually significant cataracts should be r e m o v e d at the earliest possible opportunity provided that the health of the child is n o t j e o p a r d i z e d ? 56 While infantile cataracts have b e e n r e m o v e d within the first 24 hours o f life, 96 Elston a n d Timms 66 have p r o p o s e d that the first six weeks of life represents a latent p e r i o d for binocular development. If this is true, there may be no benefit gained by very early intervention. 1. L e n s e c t o m y In 1960 Scheie TM popularized the technique o f aspirating infantile cataracts using a syringe filled with saline solution. For complete cataracts he reco m m e n d e d aspirating the lens cortex as a single p r o c e d u r e . However, o n e or m o r e discissions o f the posterior lens capsule were usually required

LAMBERT, DRACK

Fig. 16. A combined nuclear and cortical cataract with a calcific excrescence nasally (arrows). The calcific mass was excised with a vitreous cutting instrument, but in some cases must be crushed with intraocular forceps or delivered through a limbal incision.

postoperatively, m9 For partial cataracts Scheie T M r e c o m m e n d e d a two-step p r o c e d u r e , which consisted of initially n e e d l i n g the anterior capsule a n d then aspirating the cortex o f the lens several days later. With the advent of vitreous cutting instruments, it b e c a m e feasible to remove most infantile cataracts with a single operation, r e f e r r e d to as a lensectomy. In most cases, a posterior capsulotomy a n d anterior vitrectomy are p e r f o r m e d concurrently because o f the high incidence o f posterior capsular opacification in infantile eyes. Taylor 257 did n o t have to p e r f o r m any discissions in 23 infantile eyes following lensectomies, whereas 32 reoperations were r e q u i r e d in 28 eyes following lens aspiration alone. While a lensectomy can be perf o r m e d using either a limbal or pars plana approach, 2°2 most authors favor a limbal a p p r o a c h to minimize the risk o f d a m a g i n g the peripheral retina a n d to prevent vitreous f r o m b e c o m i n g incarcerated in the wound. 156 I n t r a o c u l a r scissors may be required to free the retrolenticular plaque f r o m the ciliary processes in an eye with PHPV or to o p e n a thickened anterior or posterior lens capsule. Occasionally, intraocular forceps may be helpful to crush or extract intralenticular calcific excrescences (Fig 16).142 I n t r a o c u l a r cautery may also be helpful in eyes with PHPV to prevent intraocular h e m o r r h a g i n g . Using a limbal approach, a lensectomy can be p e r f o r m e d either with o n e entry site for an infusion c a n n u l a a n d a s e c o n d for a vitreous cutting instrument, or with a single larger o p e n i n g t h r o u g h which a vitreous cutting instrum e n t with an infusion sleeve can be i n t r o d u c e d . Great care must be exercised to prevent vitreous

INFANTILE CATARACTS f r o m tracking to the incision sites as the instrum e n t s are r e m o v e d f r o m the eyes. This is best acc o m p l i s h e d by t u r n i n g off the infusion b e f o r e rem o v i n g an i n s t r u m e n t f r o m the eye. T h e limbal incisions can t h e n be closed with nylon or polyglactin suture349 Polyglactin sutures have the advantage of r e s o r b i n g while nylon sutures will occasionally e r o d e t h r o u g h the conjunctiva, irritating the u p p e r lid. While m o s t authors have advocated r e m o v i n g bilateral cataracts as two separate procedures to m i n i m i z e the risk of bilateral e n d o p h thalmitis, 9~,~39 G u o a n d coworkers 97 have a d v o c a t e d s i m u l t a n e o u s cataract surgery for selected children with bilateral infantile cataracts because of the decreased anesthetic risk, the ability to rehabilitate b o t h eyes simultaneously a n d the r e d u c e d cost o f this a p p r o a c h . T h e y did r e c o m m e n d , however, that two different sets of surgical i n s t r u m e n t s be used to minimize the risk o f e n d o p h t h a l m i t i s developing in b o t h eyes.

2. Primary IOt Implantation I n t r a o c u l a r lenses (IOLs) are n o w i m p l a n t e d in s o m e infants after cataract surgery either as a prim a r y or s e c o n d a r y p r o c e d u r e . A n u m b e r o f surgical techniques have b e e n used to i m p l a n t IOLs as a p r i m a r y p r o c e d u r e in infantile eyes. Before i m p l a n t i n g an IOL, the lens can be aspirated, using either a c o m b i n e d i r r i g a t i o n / a s p i r a t i o n device or a two-port system with an irrigation c a n n u l a in o n e p o r t a n d an aspiration device in the s e c o n d port. In o r d e r to achieve o p t i m a l c e n t r a t i o n with intracapsular fixation of the IOL, an a n t e r i o r caps u l o t o m y without radial tears n e e d s to be created. T h r e e t e c h n i q u e s m a y be used to create an anterior c a p s u l o t o m y in an infantile eye. T h e first, a c o n t i n u o u s curvilinear capsulorhexis, requires that the a n t e r i o r capsule be t o r n manually in a curvilinear fashion. 84 While this t e c h n i q u e works well in adults a n d o l d e r children, the increased elasticity of an infant's a n t e r i o r capsule frequently results in i n a d v e r t e n t p e r i p h e r a l extension o f the capsulotomy. 27° T h e second, a m e c h a n i z e d a n t e r i o r capsutectomy, is c r e a t e d using a vitreous cutting ins t r u m e n t . Using this technique, Wilson r e p o r t e d only o n e radial tear a n d n o p e r i p h e r a l extensions o f the c a p s u l o t o m y in 18 infantile eyes. 279 T h e third uses a d i a t h e r m y c a p s u l o t o m y n e e d l e (Kl6ti RF Capulotomy, O e r d i I n s t r u m e n t e , Berneck, Switzerland) to b u r n a circular o p e n i n g in the a n t e r i o r lens capsule. T h e central b u t t o n o f a n t e r i o r lens capsule can t h e n be r e m o v e d with forceps (O'Keefe M: Personal c o m m u n i c a t i o n ) . It is generally a g r e e d that intracapsular placem e n t o f an I O L is p r e f e r a b l e to optimize centration a n d minimize the contact b e t w e e n the I O L a n d uveal tissue. 5 In s o m e cases, tears in the ante-

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Fig. 1 Z The left eye of a three-year-old child following the aspiration of a traumatic cataract coupled with a mary posterior capsulotomy, anterior vitrectomy and implantation of an IOL. After a one-year follow-up, refractive error in this eye is -0.50 + 0.50 × 90 and uncorrected visual acuity is 20/30.

prithe the the

rior or p o s t e r i o r capsule p r e v e n t the haptics f r o m b e i n g placed in the capsular bag. In these instances, it is p r o b a b l y b e t t e r to place b o t h haptics in the ciliary sulcus r a t h e r t h a n place o n e haptic in the capsular b a g a n d the o t h e r in the sulcus to minimize I O L d e c e n t r a t i o n or tilting. 15 T h e m a n a g e m e n t of the p o s t e r i o r lens capsule following I O L i m p l a n t a t i o n in infants is controversial. Given the h i g h rate of p o s t e r i o r capsular opacification following cataract surgery in infantile eyes, leaving the p o s t e r i o r capsule intact will usually necessitate a s e c o n d surgical p r o c e d u r e . To red u c e the n e e d for r e o p e r a t i o n , D a h a n 5"~has advocated the creation o f a p r i m a r y p o s t e r i o r capsulot o m y with a vitreous cutting i n s t r u m e n t . T h e I O L is t h e n i m p l a n t e d in the capsular b a g (Figs. 17 a n d 18A). While this t e c h n i q u e is associated with a low r e o p e r a t i o n rate, it has the disadvantage o f increasing the risk of I O L dislocation i n t r a o p e r a t i v e l y a n d m a k e s intracapsular fixation of the haptics m o r e difficult, w4 Buckley 29 has advocated a two-staged p r o c e d u r e . T h e I O L is initially i m p l a n t e d into the capsular b a g t h r o u g h a limbal incision a n d t h e n a p o s t e r i o r c a p s u l o t o m y a n d v i t r e c t o m y is p e r f o r m e d t h r o u g h the pars p l a n a (Fig. 18B). This a p p r o a c h has the disadvantage o f r e q u i r i n g that a s e c o n d e n t r y site m u s t be created in the pars p l a n a a n d m a y also increase the risk of retinal detachm e n t later in life due to vitreous i n c a r c e r a t e d in the pars p l a n a e n t r y site. A p o s t e r i o r c a p s u l o t o m y a n d a n t e r i o r vitrectomy can also be p e r f o r m e d t h r o u g h the limbal incision after I O L i m p l a n t a t i o n by placing the vitreous cutting i n s t r u m e n t undern e a t h the I O t . 161 G i m b e l sv has advocated creating a m a n u a l p o s t e r i o r capsulorhexis a n d t h e n prolapsing the I O L optic t h r o u g h the p o s t e r i o r caps u l o t o m y (Fig. 18C). H e has h y p o t h e s i z e d that this t e c h n i q u e m a y p r e v e n t Elschnig pearls f r o m migrating into the visual axis since the a n t e r i o r a n d

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A: IOL implanted in the capsular bag after a primary posterior capsulotony and anterior vitrectomy through the limbal incision. B: Anterior vitrectomy and posterior capsulotomy being performed through a pars plana incision after implanting an IOL into the capsular bag through a limbal incision. C: IOL optic prolapsed through a primary posterior capsulotomy. The haptics remain in the capsular bag. The hyaloid face has been left intact. D: IOL implanted in the capsular bag after a primary posterior capsulorhexis. The hyaloid face has been left intact. E: Lensectomy and anterior vitrectomy being performed after implanting IOL in the ciliary sulcus. F.- YAG laser posterior capsulotomy being performed as a secondary procedure after implanting an IOL in the capsular bag. Fig. 18.

posterior capsular leaflets are in direct opposition with o n e another. This t e c h n i q u e has the disadvantage of being technically difficult. Zetterstr6m and coworkers 288 have advocated p e r f o r m i n g a m a n u a l posterior capsulotomy prior to IOL implantation with no f u r t h e r manipulation o f the IOL after its implantation into the capsular bag (Fig. 18D). Only o n e o f 21 pediatric eyes was r e p o r t e d to develop opacification o f the visual axis after undergoing cataract surgery using this p r o c e d u r e . A small capsulotomy may also be created in the posterior lens capsule prior to IOL implantation, using a d i a t h e r m y capsulotomy n e e d l e after separating the hyaloid face f r o m the posterior lens capsule with a viscoelastic agent. Tablante 256 has de-

scribed a t e c h n i q u e which involves implanting an IOL anterior to the crystalline lens t h r o u g h a limbal incision (Fig. 18E). T h e crystalline lens is t h e n r e m o v e d t h r o u g h the pars plana, leaving a rim o f capsule b e h i n d to s u p p o r t the IOL. This t e c h n i q u e has the disadvantage of n o t placing the IOL in the capsular bag and also requires a s e c o n d e n t r y site t h r o u g h the pars plana. A final a p p r o a c h involves leaving the posterior capsule intact after aspirating the lens and t h e n creating a posterior capsulotomy at a later date with a YAG laser (Fig. 18F). This a p p r o a c h requires that only o n e incision be made, and the intact posterior capsule simplifies the process of placing the IOL in the capsular bag. 274 It has the disadvantage o f necessitating a s e c o n d pro-

INFANTILE CATARACTS

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Fig. 19. Left: The right eye of a five-year-old child following a penetrating corneal injury, cataract extracuon, and IOL implantation. A YAG capsulotomy was created two weeks post-operatively, but it gradually contracted in size and the posterior capsule became so thickened that the opening could not be enlarged further with a YAG laser. Right. The same eye following a pars plana membranectomy. The visual acuity is 20/25 in this eye.

cedure, which generally m u s t be p e r f o r m e d u n d e r g e n e r a l anesthesia in an infant. In addition, the intact hyaloid face m a y act as scaffolding, increasing the risk o f s e c o n d a r y m e m b r a n e s f o r m i n g , even after the p o s t e r i o r capsule is o p e n e d . 197,27° I f this a p p r o a c h is used, the status o f the p o s t e r i o r capsule m u s t be carefully m o n i t o r e d to e n s u r e that the p o s t e r i o r capsule does n o t b e c o m e so thicke n e d as to r e q u i r e an excessive a m o u n t o f laser e n e r g y to o p e n the capsule. In s o m e cases, if the p o s t e r i o r capsule is n o t carefully m o n i t o r e d , an intraoperative m e m b r a n e c t o m y m a y be necessary to o p e n the t h i c k e n e d p o s t e r i o r capsule (Fig. 19). To m i n i m i z e the a m o u n t o f e n e r g y required, Atkinson a n d Hiles 12 a d v o c a t e d p e r f o r m i n g a prophylactic YAG c a p s u l o t o m y three weeks after I O L implantation w h e n the p o s t e r i o r capsule is left intact. Atkinson a n d Hiles 12 r e p o r t e d that two or m o r e m e m b r a n e c t o m i e s were r e q u i r e d in 25% of pediatric eyes w h e n this a p p r o a c h was used.

3. Secondary IOL Implantation Several techniques have b e e n a d v o c a t e d for secondarily i m p l a n t i n g an I O L in an aphakic infantile eye. T h e first involves placing the I O L o n the rim o f residual lens capsule after freeing it f r o m the iris with scissors or an iris spatula. 52 Iris retraction h o o k s can also b e helpful to visualize the residual lens capsule if the pupil is miotic or if a particularly large p o s t e r i o r c a p s u l o t o m y was c r e a t e d d u r i n g the lensectomy. A s e c o n d t e c h n i q u e involves suturing an I O L into the ciliary sulcus. 58,25° T h e l o n g t e r m safety of this t e c h n i q u e is n o t known, a n d in m o s t cases suture fixation is p r o b a b l y unnecessary, since an a d e q u a t e a m o u n t of capsule usually r e m a i n s to s u p p o r t the IOL. A n u m b e r o f serious complica-

tions have b e e n r e p o r t e d in eyes which have und e r g o n e suture fixation, including late e n d o p h thalmitis, I O L dislocation, a n d retinal detachm e n t 2 66 IOLs can also be i m p l a n t e d in the anter i o r c h a m b e r . A u f f a i t h a n d c o w o r k e r s 13 h a v e r e p o r t e d a relatively low c o m p l i c a t i o n rate after the i m p l a n t a t i o n o f flexible, o p e n l o o p e d IOLs into the a n t e r i o r c h a m b e r , as c o m p a r e d to rigid closed l o o p e d IOLs. Nevertheless, c o n c e r n s still exist r e g a r d i n g the l o n g t e r m safety o f an a n t e r i o r c h a m b e r I O L in an infantile e y e . 238

C. POSTOPERATIVE COMPLICATIONS T h e risk of complications d e v e l o p i n g in infantile eyes after cataract s u r g e r y is h i g h e r t h a n that in adult eyes. This difference likely reflects the increased n u m b e r o f years that an infant will live after cataract surgery, as well as the g r e a t e r inflamm a t o r y r e s p o n s e that occurs in an infantile eye after i n t r a o c u l a r surgery. 239 Certain complications such as g l a u c o m a a n d retinal d e t a c h m e n t have a g r e a t e r c h a n c e of d e v e l o p i n g the l o n g e r a p e r s o n lives, a n d since an infant will likely live for 70 or 80 years following cataract surgery, the risk of these complications d e v e l o p i n g later in life b e c o m e s quite high. While a l e n s e c t o m y has r e d u c e d the risk of certain complications d e v e l o p i n g d u r i n g the i m m e d i a t e p o s t o p e r a t i v e p e r i o d , s u c h as s e c o n d a r y m e m b r a n e s , it m a y increase the risk of o t h e r complications developing, such as retinal d e t a c h m e n t . Similarly, while I O L i m p l a n t a t i o n m a y r e d u c e the risk o f a m b l y o p i a developing, o t h e r complications m a y d e v e l o p , s u c h as I O L d e c e n t r a t i o n a n d p s e u d o p h a k i c m e m b r a n e s , sl

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Surv Ophthalmol 40 (6) May-June 1996 TABLE 6

Incidence of Glaucoma after Infantile Cataract Surgery

Author Chrousos 39 Keech130 Simon237 RobbTM Mills Iv6 Asrani 9

Incidence Open Angle (%) (%) 6 21 24 15 15 NA

NA 62 94 80 74 80

Closed Angle (%) NA 38 6 20 26 11

1. Amblyopia Amblyopia is the greatest threat to vision following infantile cataract surgery. 143 It arises because the retina receives a defocused image d u r i n g the critical p e r i o d o f visual development, and is associated with n e u r o a n a t o m i c a l changes in the lateral geniculate nuclei and the ocular d o m i n a n c e columns in the striate cortex. 26° Great vigilance is required in the optical c o r r e c t i o n of aphakic eyes and in the balancing of visual inputs to the two eyes d u r i n g the first five to six years of a child's life to p r e v e n t this complication f r o m developing? ~1

2. Posterior Capsular Opacification Posterior capsular opacification is nearly universal in infantile eyes if the posterior capsule is left intact. 6,1°5,164 In most cases the posterior capsule opacities within a few m o n t h s o f surgery. If left untreated, the retinal image quality will be severely degraded, and it may b e c o m e impossible to accurately refract the eye.

3. Secondary Membrane S e c o n d a r y m e m b r a n e s may f o r m across the pupil or over the anterior or posterior surface o f an IOL after infantile c a t a r a c t surgery. I°6,164,197,239,245 Pupillary m e m b r a n e s are particularly c o m m o n in microphthalmic eyes that u n d e r g o cataract surgery d u r i n g the neonatal period. 94,~° W h e n these membranes are relatively thin, they may be o p e n e d with a YAG laser. In m o r e advanced cases, intraocular surgery may be required. T h e incidence of secondary m e m b r a n e s may be r e d u c e d by minimizing the manipulation o f the iris intraoperatively, by applying topical corticosteroids and cycloplegic agents at f r e q u e n t intervals postoperatively, and by using h e p a r i n in the infusion solution. 146,26a

4. Glaucoma Glaucoma is one of the most c o m m o n complications o f infantile cataract surgery, with a prevalence as high as 24% (Table 6). Both o p e n angle and angle closure glaucoma may develop. Angle

LAMBERT, DRACK closure glaucoma occurs most c o m m o n l y in the i m m e d i a t e postoperative p e r i o d in m i c r o p h t h a l m ic eyes s e c o n d a r y to pupillary block. Pupillary block is usually caused by a fibrin m e m b r a n e extending across the pupil. Topical corticosteroids a n d cycloplegic agents administered postoperatively will prevent a pupillary m e m b r a n e f r o m f o r m i n g in most infantile eyes. Less commonly, pupillary block glaucoma may develop s e c o n d a r y to vitreous prolapsing into the anterior chamber. In most cases, this complication can be averted by p e r f o r m ing a d e e p a n t e r i o r vitrectomy. Pupillary block glaucoma may also develop after IOL implantation s e c o n d a r y to i r i d o - p s e u d o p h a k i c synechiae. 269a Postoperative mydriasis, topical corticosteroids and a peripheral iridectomy are all helpful in r e d u c i n g the incidence o f pupillary block glaucoma. 68,~76 Less commonly, chronic angle closure glaucoma may develop in infantile eyes after cataract surgery. 71,13° Chronic angle closure glaucoma has b e e n n o t e d to o c c u r less frequently after a lensectomy than after lens aspiration, presumably because the lens cortex is m o r e completely r e m o v e d ? T h e most c o m m o n type o f glaucoma to develop after infantile cataract surgery is o p e n angle glaucoma. Unlike angle closure glaucoma, which usually develops soon after surgery, o p e n angle glauc o m a is not usually diagnosed until years later. Simon and coworkers 237 r e p o r t e d a m e a n interval o f 6.8 years f r o m the time of cataract surgery until glaucoma was diagnosed, while Phelps and coworkers 2°s r e p o r t e d intervals ranging f r o m six to 56 years. Gonioscopy of these eyes generally reveals a d e e p anterior chamber, increased p i g m e n t a t i o n o f the trabecular meshwork, and the iris inserting into the posterior aspect of the trabecular meshwork. 9,2°~,22I Peripheral anterior synechiae are usually c o n f i n e d to the area o f the surgical incision. While certain eyes are predisposed to develop o p e n angle glaucoma and may have developed glaucoma even if they had n o t u n d e r g o n e cataract extraction, surgery may accelerate the developm e n t o f glaucoma in these eyes. In s u p p o r t of a causal relationship for infantile cataract surgery and the d e v e l o p m e n t of o p e n angle glaucoma, Simon and coworkers 237 n o t e d that glaucoma developed only in t h e eye that u n d e r w e n t cataract surgery in a child with bilateral cataracts. T h e y speculated that a substance in the vitreous h u m o r diffuses forward and damages the trabecular meshwork following infantile cataract surgery. Microcornea and the congenital rubella syndrome have b o t h b e e n identified as risk factors for the develo p m e n t o f o p e n angle g l a u c o m a J 2~,~76O p e n angle glaucoma appears to o c c u r with equal f r e q u e n c y after lens aspiration or a lensectomy c o u p l e d with an a n t e r i o r v i t r e c t o m y 9 ,~76

INFANTILE CATARACTS T h e diagnosis o f g l a u c o m a m a y be difficult to establish in children after cataract surgery since they often lack the classical signs o f congenital glaucoma, such as b u p h t h a l m i a , e p i p h o r a a n d b l e p h a r o s p a s m . Moreover, the i n t r a o c u l a r pressure may be difficult to m e a s u r e with the child awake, a n d the view o f the optic disk m a y be c o m p r o m i s e d by lens r e m n a n t s , miosis, a n d nystagmus. In addition, visual fields usually c a n n o t be accurately assessed until later in childhood. E g b e r t a n d Kushn e r 61 n o t e d that an excessive loss o f h y p e r o p i a was often a sign o f g l a u c o m a in children following cataract surgery. Asrani a n d Wilensky 9 have r e c o m m e n d e d a s c r e e n i n g e x a m i n a t i o n for g l a u c o m a after infantile cataract surgery every t h r e e m o n t h s d u r i n g the first postoperative year, twice yearly until the t e n t h year, a n d a n n u a l l y thereafter. W h e n an a d e q u a t e e x a m i n a t i o n c a n n o t be o b t a i n e d while a child is awake, an e x a m i n a t i o n should b e p e r f o r m e d u n d e r sedation or general anesthesia if there is a high suspicion of glaucoma. While m e d ical t r e a t m e n t should be tried first to lower the i n t r a o c u l a r pressure, a surgical p r o c e d u r e is often r e q u i r e d to a d e q u a t e l y control the i n t r a o c u l a r p r e s s u r e . 16a'19°a'269a Even with surgery, it can be difficult to lower the i n t r a o c u l a r pressure into the n o r m a l range. 19° 5. Retinal Detachment R h e g m a t o g e n o u s retinal d e t a c h m e n t s are usually a late c o m p l i c a t i o n o f infantile cataract surgery. In t h r e e large series, the m e a n interval f r o m infantile cataract surgery to retinal d e t a c h m e n t r a n g e d f r o m 23 to 34 y e a r s . I17,125,171,261 Thus, while the incidence o f retinal d e t a c h m e n t following infantile cataract surgery has b e e n r e p o r t e d to be similar to that o c c u r r i n g after adult cataract surgery, these figures are p r o b a b l y underestimates, given their relatively s h o r t - t e r m follow-ups? 9,57 Retinal d e t a c h m e n t s following infantile cataract surg e r y are usually r h e g m a t o g e n o u s s e c o n d a r y to oval or r o u n d holes a l o n g the p o s t e r i o r vitreous base. Most of these eyes also have vitreoretinal changes indicative of traction o n the p e r i p h e r a l retina, which likely contributes to the f o r m a t i o n o f these holes. Factors which increase the risk of retinal det a c h m e n t following infantile cataract surgery include high m y o p i a a n d r e o p e r a t i o n s ? 3°,221 Five o f the six children d e v e l o p i n g retinal d e t a c h m e n t in a series r e p o r t e d by Chrousos a n d coworkers 39 h a d u n d e r g o n e r e o p e r a t i o n s to o p e n s e c o n d a r y m e m branes. R e o p e r a t i o n s using a pars p l a n a a p p r o a c h are particuIarly h a z a r d o u s because o f the risk o f d a m a g i n g the p e r i p h e r a l retina a n d because o f the traction e x e r t e d o n the p e r i p h e r a l retina by vitreous i n c a r c e r a t e d in the e n t r y site. While s o m e authors have suggested that a l e n s e c t o m y with ante-

443 rior vitrectomy m a y be associated with a lower incidence of retinal d e t a c h m e n t t h a n a lens aspiration alone, m a n y m o r e years o f follow-up will be necessary b e f o r e this can be proven. ~9 While a lensectomy is associated with a lower incidence o f reoperations, 39,257 the addition of an a n t e r i o r vitrect o m y likely hastens the d e v e l o p m e n t of a p o s t e r i o r vitreous d e t a c h m e n t , which m a y increase the risk of retinal d e t a c h m e n t . T h e t r e a t m e n t o f retinal det a c h m e n t s following infantile cataract surgery is frequently h a m p e r e d by mi0sis, nystagmus a n d lens r e m n a n t s , which m a k e it m o r e difficult to identify retinal breaks. Even w h e n the retina is successfully reattached, the visual result is usually p o o r . 117

6. Endophthalmitis E n d o p h t h a l m i t i s is o n e of the m o s t serious complications that can o c c u r after infantile cataract surgery. It has b e e n r e p o r t e d to have a prevalence o f 7/10,000 surgeries, which is similar to the preva l e n c e r e p o r t e d f o l l o w i n g c a t a r a c t s u r g e r y in adults. 12s,27~ In m o s t cases, it is d i a g n o s e d within several days o f cataract surgery. It is m o s t frequently caused by Staphylococcus aureus, Staphylococcus ep-

idermidis, Streptococcus pneumoniae and Streptococcus viridans. Nasolacrimal d u c t obstruction, periorbital e c z e m a a n d u p p e r respiratory infection are important risk factors for the d e v e l o p m e n t of postoperative e n d o p h t h a l m i t i s ? 2 For this reason, nasolacrimal d u c t obstructions should be t r e a t e d p r i o r to cataract surgery, a n d cataract surgery should be p o s t p o n e d in an infant with an u p p e r respiratory infection. Most children have a p o o r visual outc o m e following e n d o p h t h a l m i t i s . In o n e series, 65% of the eyes d e v e l o p i n g postoperative e n d o phthalmitis h a d a final visual acuity o f n o light perception. 275

7. Lens Reproliferation Lens reproliferation occurs universally in infantile eyes after cataract surgery. 6 It usually occurs in the retro-irido space a n d b e c o m e s e n c a p s u l a t e d within the r e m n a n t s o f the a n t e r i o r a n d p o s t e r i o r lens capsules. W h e n e n c a p s u l a t e d in the lens capsule, this o p a q u e lens material is r e f e r r e d to as S o e m m e r r i n g ' s ring. 126 Occasionally, reproliferating lens material may e x t e n d into the pupillary o p e n i n g a n d o b s t r u c t the visual axis (Fig. 20).2.184 This m a y o c c u r m o r e frequently w h e n radial tears are p r e s e n t in the a n t e r i o r lens capsule. 6

8. Postoperative Inflammation S o m e i n f l a m m a t i o n invariably occurs postoperatively after cataract surgery. J a m e s o n a n d coworkers 12° described n i n e children with severe pain, p h o t o p h o b i a a n d con]unctival injection following

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Fig. 21. Corneal edema and inflammation of the left eye two weeks following an uncomplicated lensectomy and anterior vitrectomy in a four-year-old child. The corneal edema and inflammation resolved after a protracted course of topical corticosteroids.

10. Cystoid Macular Edema

Fig. 20. Lens reproliferation obstructing the pupillary axis in a microphthalmic eye six months following cataract extraction. A reoperation was performed to remove the reproliferating lens material.

cataract surgery, which they called clinically significant postoperative i n f l a m m a t i o n (Fig. 21). Postoperative i n f l a m m a t i o n can be m i n i m i z e d by applying topical corticosteroids at f r e q u e n t intervals a n d by avoiding any intraoperative m a n i p u l a t i o n of the iris. Wilson-Holt a n d coworkers 2s° have also described uveitis d e v e l o p i n g in the fellow eye o f a child following the i m p l a n t a t i o n o f an iris-supporte d IOL, suggesting sympathetic o p h t h a l m i a . 9. H e m o r r h a g i c R e t i n o p a t h y A h e m o r r h a g i c r e t i n o p a t h y has b e e n r e p o r t e d to o c c u r in u p to one-third o f eyes after infantile cataract s u r g e r y Y ,175 T h e h e m o r r h a g e s are usually f l a m e - s h a p e d a n d m a y be associated with a conc u r r e n t vitreous h e m o r r h a g e . T h e h e m o r r h a g e s develop d u r i n g the first 24 h o u r s following surgery, are nonprogressive, a n d usually resolve within t h r e e weeks. W h e n p r e s e n t in the fovea, they m a y cause p r o f o u n d visual loss a n d amblyopia. T h e y have b e e n attributed to vitreous traction o n retinal vessels, a Valsalva m a n e u v e r d u r i n g the perioperative period, h y p o t o n y or venous stasis retinopathy. 37 N o n e o f the patients studied thus far with this c o m p l i c a t i o n have h a d a c o a g u l o p a t h y or clinically significant anemia.

Cystoid m a c u l a r e d e m a (CME) is a rare complication following cataract surgery d u r i n g infancy. 78'82"94'183'206 While o n e r e p o r t described CME dev e l o p i n g c o m m o n l y in infantile eyes after lensectomies a n d a n t e r i o r vitrectomies, its p r e s e n c e was n o t d o c u m e n t e d p h o t o g r a p h i c a l l y a n d its appeara n c e was atypical. 11~ O t h e r s have n o t e d a very low incidence o f CME following cataract surgery during infancy. 7s,s2,o4,1s3,~°6 Because o f the difficulty o f p e r f o r m i n g fluorescein angiogTaphy d u r i n g infancy, surgeons s e l d o m evaluate children for this complication. Infants p r o b a b l y develop CME less comm o n l y after cataract surgery t h a n adults because their retinal vasculature is generally healthier.

11. Corneal Edema T r a n s i e n t corneal d e c o m p e n s a t i o n may o c c u r after congenital cataract surgery, b u t bullous keratopathy is a rare complication. W o t r u b a 272 n o t e d the endothelial cell c o u n t in 26 children who h a d u n d e r g o n e cataract surgery to be similar to that o f n o r m a l children, suggesting that cataract extraction by itself does n o t result in a significant reduction in the endothelial cell c o u n t in children. Bullous k e r a t o p a t h y is m o r e c o m m o n l y seen in infantile eyes following I O L i m p l a n t a t i o n a n d m a y rarely r e q u i r e p e n e t r a t i n g k e r a t o p l a s t y . 227 C o r n e a l d e c o m p e n s a t i o n m a y also o c c u r if d e t e r g e n t s used d u r i n g the cleaning of cannulas or i n s t r u m e n t s are n o t t h o r o u g h l y rinsed off b e f o r e they are introd u c e d into the a n t e r i o r chamber. 195

12. Pupillary Abnormalities Pupillary a b n o r m a l i t i e s are fairly c o m m o n after infantile cataract surgery. In s o m e instances, the iris s p h i n c t e r muscle is d a m a g e d intraoperatively by a vitreous cutting i n s t r u m e n t , while in o t h e r instances the iris is d a m a g e d w h e n it prolapses out o f the eye d u r i n g surgery. Lightly colored irides are particularly susceptible to injury d u e to their

INFANTILE CATARACTS

445

Fig. 23.

Pupillary capture of an IOL optic (arrows) in a three-year-old child. The visual acuity is 20/20 in this eye.

Fig. 22.

A vitreous strand tracking through the pupil to the limbus at 11 o'clock.

m o r e d i a p h a n o u s nature. Vitreous wicks to limbal incision sites may also distort the pupil (Fig. 22). Pupillary irregularities are particularly c o m m o n after I O L implantation s e c o n d a r y to posterior synechiae. 147,197 In addition, pupils frequently b e c o m e immobile a n d miotic after infantile cataract surgery. T h e degree o f p e r m a n e n t miosis may be mitigated somewhat by the use o f topical cycloplegic agents postoperatively.

13. I O L D e c e n t r a t i o n D e c e n t r a t i o n o f an I O L is n o t u n c o m m o n after I O L implantation d u r i n g infancy (Fig. 23). It has b e e n p r o p o s e d that intracapsular p l a c e m e n t o f an I O L will r e d u c e the incidence of this complication. al Hiles a°5 r e p o r t e d a 40% incidence of lens malpositioning in pediatric eyes following posterior c h a m b e r I O L implantation. In some cases, explanting or repositioning an I O L may be necessary. I O L dislocation is particularly a p r o b l e m with iris s u p p o r t e d IOLs. s~

VI. Visual Rehabilitation In o r d e r to visually rehabilitate an infantile eye after cataract extraction, the eye must be focused optically a n d therapy must be initiated to treat and prevent the f u r t h e r d e v e l o p m e n t o f amblyopia. A. OPTICAL CORRECTION A variety o f m e a n s are available to optically correct infantile eyes after cataract extraction, including contact lenses, spectacles, epikeratoplasty a n d intraocular lenses.

1. Contact L e n s e s C o n t a c t Ienses have b e e n the standard m e a n s o f optically c o r r e c t i n g infantile eyes after surgery.

T h e major advantage of contact lenses is that their power can be easily adjusted as infantile eyes elongate. This is an i m p o r t a n t consideration since several authors have r e p o r t e d a m e a n decrease of 9 diopters (D) in the contact lens c o r r e c t i o n of child r e n d u r i n g the first four years o f life. 57,I79 T h e major p r o b l e m associated with contact lens use is n o n c o m p l i a n c e . Contact lens n o n c o m p l i a n c e is particularly a p r o b l e m for children with m o n o c u lar aphakia. Assaf a n d coworkers 1° r e p o r t e d that only 44% o f children with unilateral aphakia were wearing their contact lens w h e n they r e t u r n e d for follow-up appointments. T h e reasons they cited for n o n c o m p l i a n c e included the loss o f lenses, conjunctival erythema, a n d a p o o r fit. C o m p l i a n c e is particularly difficult for children who are 1% to 3 years of age. 2,111 N e u m a n n a n d coworkers 194 rep o r t e d a lens loss rate of 4.2 lenses p e r year d u r i n g the first year o f lens use a n d then two lenses per year d u r i n g the s e c o n d year o f lens use; however, the rate o f lens loss varies considerably f r o m child to child a n d with different types o f contact lenses. 2,3 Contact lens use can also result in a n u m b e r o f corneal complications, including infectious keratitis, c o r n e a l vascularization a n d hypoxic corneal ulcerations. H°,158 Silicone lenses may a d h e r e to the c o r n e a a n d p r o d u c e the s u c k e d - o n lens synd r o m e . 177While some authors have advocated daily wear contact lenses, S e x t e n d e d wear contact lenses c o n t i n u e to be prescribed because o f the difficulty parents have in inserting a n d removing contact lenses. 9 It is i m p o r t a n t that parents u n d e r s t a n d that the risk o f ulcerative keratitis increases by 6 8-fold w h e n c o n t a c t lenses are w o r n overnight. 9°,2°7,232,2~3While silicone lenses were the pred o m i n a n t type o f contact lenses used to correct infantile aphakia in the past, rigid gas p e r m e a b l e lenses are now b e i n g used with greater f r e q u e n c y

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because o f their s u p e r i o r ability to neutralize astigmatism, lower cost, a n d availability in a wider r a n g e of powers?

2. Spectacles Aphakic spectacles are generally n o t suitable for children with unilateral aphakia, 63,181 b u t provide a satisfactory c o r r e c t i o n for m a n y children with bilateral aphakia. 14° Like contact lenses, their p o w e r can be readily c h a n g e d to c o m p e n s a t e for ocular growth, b u t they have the disadvantage o f p o o r cosmesis a n d inferior optics. A variety o f optical distortions, such as ring scotomas, are i n d u c e d by the high p o w e r e d corrections r e q u i r e d for m o s t infants. If c o m p l i a n c e with contact lens use is poor, spectacles can be w o r n for a p e r i o d o f time a n d t h e n contact lenses can be r e i n t r o d u c e d w h e n the child is older, m E n o c h a n d H a m e r 67 have described a t e c h n i q u e for r e d u c i n g the aniseikonia i n d u c e d by high plus contact lenses in unilateral a p h a k e s by overplussing the aphakic eye with a contact lens a n d t h e n c o r r e c t i n g the i n d u c e d myopia with spectacles.

3. Epikeratoplasty E p i k e r a t o p l a s t y was i n t r o d u c e d in t h e e a r l y 1980s as an alternative m e a n s o f optically correcting aphakic eyes. It consisted o f suturing a partial thickness lamellar graft o n t o the surface o f the cornea. T h e p r o c e d u r e p r o v e d to be unsatisfactory in infants because 1) the grafted lenticule would rem a i n hazy for an e x t e n d e d p e r i o d o f time after surgery, placing these eyes at risk for amblyopia; a n d 2) c o n t i n u e d axial e l o n g a t i o n c a u s e d a m a r k e d myopic shift. 7

4. Intraocular Lenses Intraocular lenses are now the p r e f e r r e d m e a n s of optically correcting aphakia in adults. While they are rapidly b e c o m i n g the p r e f e r r e d m e a n s of optically correcting older children as w e l l , 86,98,108,134,136,278 controversy still exists r e g a r d i n g the advisability o f i m p l a n t i n g an I O L in an infantile eye. IOLs have the advantage of providing a full-time c o r r e c t i o n o f an aphakic eye with optics which closely simulate those of the crystalline lens. T h e y have the disadvantage o f b e i n g difficult to e x c h a n g e if a myopic shift develops in an infantile e y e . 182 While the axial length o f a n o r m a l phakic eye grows an average o f 2.4 to 3.3 m m d u r i n g the first year of life a n d an additional 1.2 to 2.2 m m d u r i n g the s e c o n d year o f l i f e , 93'16a eyes m a d e aphakic or p s e u d o p h a k ic d u r i n g early infancy m a y grow less than this. 163 Using a Rhesus m o n k e y m o d e l , it has b e e n shown that eyes m a d e aphakic or p s e u d o p h a k i c d u r i n g infancy grow o n average 2.0 m m less t h a n their fellow phakie eyes.147 This r e t a r d a t i o n o f axial elon-

LAMBERT, DRACK gation may o c c u r s e c o n d a r y to visual deprivation, physical changes in the eye d u e to the disruption of the lens zonules or the absence of growth factors p r o d u c e d by the crystalline lens. 49~,u4a,259,27a However, even with this r e t a r d a t i o n o f axial elongation, p s e u d o p h a k i c infantile eyes still e x p e r i e n c e a significant myopic shift. 2s9 Moreover, e x t e n d e d periods o f visual deprivation s e c o n d a r y to a cataract or u n c o r r e c t e d a p h a k i a m a y have the opposite effect on an infantile eye a n d cause excessive axial elongation.n4,163,178,212,214,271,285 A variety of a p p r o a c h e s have b e e n utilized to try to c o m p e n s a t e for the e x p e c t e d myopic shift which occurs in an infantile eye after cataract extraction a n d I O L implantation. S o m e surgeons have imp l a n t e d IOLs with a p o w e r that would be a p p r o priate for an adult eye, b a s e d on the a s s u m p t i o n that these eyes will grow n o r m a l l y after the crystalline lens is r e m o v e d ? 1,a°a,2s8 T h e disadvantage o f this a p p r o a c h is that these eyes will be significantly u n d e r c o r r e c t e d d u r i n g infancy a n d m a y r e m a i n u n d e r c o r r e c t e d t h r o u g h o u t life if the axial elongation o f these eyes is r e t a r d e d by the extraction o f the crystalline l e n s ? a O t h e r authors have fav o r e d i m p l a n t i n g an I O L with a p o w e r closer to that p r e d i c t e d for i m m e d i a t e e m m e t r o p i a , a r g u i n g that infancy is the time in life w h e n the visual syst e m is m o s t sensitive to optical d e f o c u s . 53'86"258a'270 T h e y have e m p h a s i z e d that a m b l y o p i a can be irreversible, whereas an I O L with the w r o n g p o w e r can usually b e e x c h a n g e d , s6 Buckley 29 has advocated an i n t e r m e d i a t e a p p r o a c h , i m p l a n t i n g an I O L 3 D less t h a n p r e d i c t e d for a one-year-old child; however, he did n o t m a k e any r e c o m m e n d a t i o n s r e g a r d i n g the m o s t a p p r o p r i a t e lens p o w e r to imp l a n t in an infantile eye d u r i n g the first year o f life. Sinskey 239 i m p l a n t e d in a 17-day-old infant a 24.5 D IOL, which was 8 D less t h a n p r e d i c t e d for e m m e t r o p i a . After 18 m o n t h s o f follow-up, the child r e m a i n e d u n d e r c o r r e c t e d by over 5 D in this eye. It is the o p i n i o n o f the authors that an I O L i m p l a n t e d in an infantile eye should leave the eye slightly u n d e r c o r r e c t e d . However, it is n o t a p p r o priate to i m p l a n t an I O L with a p o w e r o f 19-20 D, since this will usually leave these eyes severely und e r c o r r e c t e d d u r i n g the i m p o r t a n t formative years o f visual d e v e l o p m e n t a n d p e r h a p s t h r o u g h o u t life, given the a p p a r e n t r e d u c t i o n o f axial growth that m a y o c c u r after the removal of the crystalline lens d u r i n g infancy. T h e size a n d characteristics o f an I O L are also i m p o r t a n t considerations, given the smaller size o f an infantile eye a n d the growth that occurs after I O L implantation. In addition, it is i m p o r t a n t to r e m e m b e r that an I O L i m p l a n t e d in an infantile eye m a y r e m a i n in this eye for 70-80 years. T h e d i a m e t e r o f the crystalline lens is 7 m m at birth,

INFANTILE CATARACTS b u t increases to 9 m m by the time a child is two years o f age. 277 In c o m p a r i s o n , adult lenses have a m e a n d i a m e t e r o f 9.6 + 0.39 m m . n T h e overall d i a m e t e r of I O L s s h o u l d b e downsized to take into consideration this difference in capsular b a g size. A 12 m m d i a m e t e r I O L a p p e a r s to b e well tolerated in m o s t infantile eyes. 53 h n p l a n t i n g too large a lens m a y result in distortion o f the capsular b a g a n d possibly erosion o f the haptic t h r o u g h the capsular bag. T h e characteristics o f the haptics are also i m p o r t a n t . In a m o n k e y m o d e l o f n e o n a t a l pseud o p h a k i a , o n e or b o t h haptics b r o k e in one-third of eyes which h a d one-piece all p o l y m e t h y l m e t h acrylate IOLs i m p l a n t e d into the p o s t e r i o r c h a m b e r a m e a n o f 21 m o n t h s after their implantation. 146,148 T h e haptic b r e a k a g e p r e s u m a b l y occ u r r e d s e c o n d a r y to stress p l a c e d on the optic-haptic j u n c t i o n as these eyes grew a n d the haptics were displaced by S o e m m e r r i n g ' s rings. T h e overall dia m e t e r o f these I O L s (10 ram) were also p r o b a b l y too large f o r these n e o n a t a l eyes a n d s o m e were i m p l a n t e d in the ciliary sulcus instead o f the capsular bag. This c o m p l i c a t i o n m a y be p r e v e n t a b l e by i m p l a n t i n g I O L s with smaller d i a m e t e r s a n d m o r e flexible haptics into the capsular bag. Cs h a p e d haptics m a y also be a d v a n t a g e o u s because they m i n i m i z e the central m i g r a t i o n o f lens epithelial cells a n d create a m o r e symmetrical radial stretch o f the p o s t e r i o r lens capsule. 6 Multifocal IOLs have certain theoretical advantages over m o n o f o c a l I O L s in providing s i m u l t a n e o u s n e a r a n d distance vision, b u t have the disadvantage o f r e d u c i n g contrast sensitivity. 85,225 Using a m o n k e y m o d e l for unilateral infantile p s e u d o p h a k i a , the visual o u t c o m e was similar for m o n k e y s with multifocal a n d m o n o f o c a l IOLs. 145 B. A M B L Y O P I A T H E R A P Y

Infantile eyes with cataracts severe e n o u g h to require cataract surgery will have s o m e d e g r e e o f amblyopia if s u r g e r y is delayed b e y o n d a latent period, which has b e e n p o s t u l a t e d to e x t e n d over the first six weeks o f an infant's life. aa Since all o f the currently available m e a n s o f optically c o r r e c t i n g an eye after cataract extraction fail to fully r e p r o d u c e all o f the optical p r o p e r t i e s o f the crystalline lens, a m b l y o p i a will also develop postoperatively in child r e n with unilateral cataracts unless the fellow eye is o c c l u d e d part-time or penalized optically or pharmacologically. 1. Animal Studies Studies using a m o n k e y m o d e l o f m o n o c u l a r a p h a k i a have p r o v i d e d valuable insights r e g a r d i n g the t r e a t m e n t o f aphakic amblyopia. T h e Rhesus m o n k e y was c h o s e n for these studies because its visual acuity is similar to that o f h u m a n s a n d its

447 visual system m a t u r e s 3 - 4 times m o r e rapidly t h a n h u m a n s , allowing e x p e r i m e n t s to be c o n d u c t e d over a s h o r t e r p e r i o d o f time. 22 T h e initial experiments consisted o f unilateral lensectomies in a g r o u p of n e w b o r n monkeys. S o m e o f the aphakic eyes were t h e n c o r r e c t e d to a n e a r p o i n t with an e x t e n d e d wear contact lens, while others were left u n c o r r e c t e d . T h e fellow eyes were t h e n treated with a r a n g e o f occlusion r e g i m e n s using o p a q u e contact lenses a n d r a n g i n g f r o m n o occlusion to full-time occlusion. Monkeys with n e a r p o i n t corrected aphakic eyes whose fellow eyes were occluded full-time h a d only a slight r e d u c t i o n in visual acuity, while their fellow eyes h a d severe occlusion amblyopia, m6 Monkeys with n e a r p o i n t c o r r e c t e d aphakic eyes who h a d their fellow eyes o c c l u d e d for 75-90% o f the daylight h o u r s h a d only a mild r e d u c t i o n in visual acuity in their aphakic eyes, while their fellow eyes h a d n o r m a l visual acuity. Monkeys with n e a r p o i n t c o r r e c t e d aphakic eyes, w h o h a d their fellow eyes o c c l u d e d for 25-50% o f the daylight hours, h a d a m o d e r a t e r e d u c t i o n in visual acuity in their aphakic eyes, b u t n o r m a l visual acuity in their fellow eyes. Finally, m o n k e y s whose aphakic eyes were left u n c o r r e c t e d , while their fellow eyes were left u n t r e a t e d , h a d only light p e r c e p t i o n vision in their aphakic eyes. Subseq u e n t studies have b e e n p e r f o r m e d evaluating the efficacy o f providing a distance c o r r e c t i o n for the aphakic eye a n d a n e a r p o i n t c o r r e c t i o n for the fellow eye. 26 In t h e o r y this would m e a n that whenever the m o n k e y l o o k e d at an object in the distance the aphakic eye would be used, whereas w h e n the m o n k e y l o o k e d at an object at n e a r the fellow eye would be used since the o t h e r eye would be defocused. While b o t h eyes d e v e l o p e d n o r m a l visual acuity d u r i n g early infancy, the visual acuity o f the m o n k e y s as juveniles b e c a m e r e d u c e d in all o f the aphakic eyes, a n d the final o u t c o m e was p o o r e r than that o c c u r r i n g w h e n the fellow eye was o c c l u d e d part-time. 26 Studies were t h e n p e r f o r m e d to evaluate the efficacy o f IOLs in optically correcting an infantile m o n k e y eye. A translucent contact lens was p l a c e d o n o n e eye o f a m o n k e y several h o u r s after birth to simulate a congenital cataract (Fig. 24).144 T h e lens was t h e n r e m o v e d in this eye w h e n the m o n k e y was two weeks o f age, a n d a m o n o f o c a l or multifocal I O L was i m p l a n t e d into the p o s t e r i o r c h a m b e r (Fig. 25). All of the pseud o p h a k i c eyes were t h e n c o r r e c t e d to a n e a r p o i n t with an e x t e n d e d wear contact lens while the fellow eyes were r a n d o m i z e d to n o occlusion or 70% occlusion therapy. While all of the p s e u d o p h a k i c eyes h a d similar grating acuities using f o r c e d choice p r e f e r e n t i a l looking d u r i n g the first six m o n t h s o f life, ~45 only the m o n k e y s w h o h a d parttime occlusion o f the fellow eyes c o n t i n u e d to have

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Fig. 24. An infantile Rhesus monkey with a translucent contact lens on the right eye simulating a mild congenital cataract.

excellent grating acuities in b o t h eyes w h e n they were tested with o p e r a n t techniques as juveniles a n d adults. 2s While the contrast sensitivity a n d optotype acuities were b e t t e r in the p s e u d o p h a k i c eyes of the m o n k e y s who h a d part-time occlusion t h e r a p y o f their fellow eyes t h a n in the m o n k e y s who h a d no part-time occlusion therapy, it was still r e d u c e d in these eyes c o m p a r e d to their fellow eyes a n d n o r m a l m o n k e y eyes. T h e s e results suggest that part-time occlusion t h e r a p y is r e q u i r e d to optimize the visual o u t c o m e o f p s e u d o p h a k i c infantile eyes.

2. Occlusion Therapy A wide variety o f occlusion r e g i m e n s have b e e n used in infants with unilateral a p h a k i a r a n g i n g f r o m 50% to nearly full-time occlusion of the fellow eye. 11~,151a Several authors have r e c o m m e n d e d increasing the p e r c e n t a g e of time the fellow eye is o c c l u d e d after the first year of life, ls,2°,57,96,15s,2~° while others have c o n t i n u e d the same occlusion r e g i m e n t h r o u g h o u t early childhood. Most authors have r e c o m m e n d e d c o n t i n u i n g occlusion t h e r a p y until a child is b e y o n d the sensitive p e r i o d o f visual d e v e l o p m e n t , which ends w h e n a child is six to seven years of age. TM O t h e r s have r e c o m m e n d e d discontinuing occlusion t h e r a p y after a child is f o u r years o f age to m i n i m i z e the chance o f develo p m e n t of diplopia. TM C o m p l i a n c e with occlusion t h e r a p y can be quite difficult, 2~a a n d p o o r visual o u t c o m e s are often a c o n s e q u e n c e of n o n c o m p l i ance with occlusion therapy? s°,lsl Catalano a n d coworkers 3~ titrated the occlusion o f the fellow eye in a g r o u p of children with m o n o c u l a r a p h a k i a f r o m 25-100%, b a s e d on the p r e f e r e n t i a l looking acuity o f the aphakic eye, b u t n o t e d no i m p r o v e m e n t in the visual o u t c o m e of these children as c o m p a r e d to children who received a standardized occlusion r e g i m e n . T h e y c o n c l u d e d that c o m p l i a n c e with oc-

LAMBERT, DRACK

Fig. 25. An infantile Rhesus monkey eye five months after the implantation of a monofocal IOL. The pupil is immobile and pigmented precipitates are present on the anterior surface of the IOL.

clusion therapy, r a t h e r t h a n differences in occlusion regimens, is the m a j o r d e t e r m i n a n t o f a g o o d visual o u t c o m e in unilaterally a p h a k i c children. In contrast, Lloyd a n d coworkers 157a r e p o r t e d preferential looking acuities to be a helpful tool in m o d ulating the occlusion r e g i m e n o f 10 infants with m o n o c u l a r aphakia. Occlusion t h e r a p y is also r e q u i r e d in s o m e child r e n with bilateral cataracts. Visual acuity a n d fixation p r e f e r e n c e s should be carefully m o n i t o r e d a n d occlusion therapy o f the n o n p r e f e r r e d eye should be instituted w h e n a significant i n t e r o c u l a r difference in visual acuity is detected.

3. Pharmacological Penalization P h a r m a c o l o g i c a l penalization o f the fellow eye is an established m e t h o d o f treating mild anisometropic a n d strabismic a m b l y o p i a Y s It is usually ineffective in children with a m b l y o p i a s e c o n d a r y to unilateral a p h a k i a due to the severity o f their amblyopia. It is also ineffective in children with bilateral a p h a k i a since their eyes can n o l o n g e r accommodate. VII.

Outcome

A. VISUAL ACUITY T h e visual o u t c o m e of eyes with infantile onset cataracts is d e p e n d e n t o n m a n y factors, including the age w h e n the cataracts develop, the density o f the cataracts, the age at which optical c o r r e c t i o n is initiated, a n d the d e g r e e with which the fellow eye is occluded. 21°,22°,2z~ Since it is often difficult to k n o w precisely w h e n a cataract d e v e l o p e d in a child a n d to quantify its density, m o s t authors have evaluated visual o u t c o m e s in r e f e r e n c e to the age

INFANTILE CATARACTS

449

TABLE 7

TABLE 8

Visual Outcomes with Unilateral Infantile Cataracts Corrected with Contact Lenses

Visual Outcomes with Unilateral Infantile Cataracts Corrected with Intraocular Lenses

# of

Author

Year

Patients

Birch 2° Drummond57 Birch 21 Neumann TM Lorenz159

1988 1989 1993 1993 1994

19 13 14 14 17

Best Corrected Visual Acuity (%) $ 20/ 40

20/5020/100

$ 20/ 200

l1 24 50 14 8

42 38 36 14 34

47 38 14 72 58

at surgery a n d c o m p l i a n c e with optical a n d occlusion therapy. Birch 21 c o m p a r e d the visual outcomes o f children with unilateral cataracts treated d u r i n g the first six weeks o f life with those treated at two to eight m o n t h s o f age. T h e m e a n recognition acuity for the children treated d u r i n g the first six weeks o f life was 2 0 / 4 0 c o m p a r e d to 2 0 / 100 for the children treated at two to eight m o n t h s o f age, suggesting that early t r e a t m e n t is associated with a better visual o u t c o m e . 21 T h e contrast sensitivity o f the children treated at any earlier age was also superior. T h e difference in visual o u t c o m e app e a r e d to be largely due to the fact that the child r e n treated d u r i n g the first six weeks o f life continued to show visual i m p r o v e m e n t until they were 37 m o n t h s o f age, whereas the visual p e r f o r m a n c e o f the o t h e r children plateaued when they were 13-18 m o n t h s o f age. Similarly, M a u r e r a n d Lewis 167 r e p o r t e d a better visual o u t c o m e ( 2 0 / 4 0 - 2 0 / 80) for children with unilateral cataracts who were treated d u r i n g the first five m o n t h s o f life a n d were c o m p l i a n t with occlusion therapy c o m p a r e d to children who were treated when older a n d were n o n c o m p l i a n t with occlusion therapy. T h e best visual o u t c o m e s o f children with bilateral cataracts have also b e e n r e p o r t e d in children who underwent early treatment. 15h In addition, the density a n d size o f a cataract is clearly i m p o r t a n t in determ i n i n g the visual o u t c o m e . ParEs 2°~ has suggested that the type o f cataract correlates better than any o t h e r factor with the visual o u t c o m e . H e n o t e d that lamellar a n d posterior lentiglobus cataracts were associated with the best visual outcomes. T h e type o f optical c o r r e c t i o n has n o t b e e n convincingly shown to influence the visual o u t c o m e s (Tables 7 a n d 8). Nystagmus a n d m i c r o p h t h a l m o s have b e e n r e p o r t e d to be p o o r prognostic signs. 79 T h e fellow eyes o f children with unilateral cataracts have b e e n r e p o r t e d to have r e d u c e d vision. T h e d e v e l o p m e n t o f bilateral manifest nystagmus is the most c o m m o n reason for r e d u c e d vision in these eyes. T M Children with unilateral aphakia a n d

Best Corrected Visual Acuity (%)

# of

Author

Year

Patients

$ 20/ 40

20/5020/100

$ 20/ 200

Burke 31 Dahan 53 Cheng 36 Markham TM

1989 1990 1991 1992

4 13 10 7

0 8 10 0

25 23 0 86

75 69 90 14

a manifest nystagmus will often a d o p t a h e a d turn to take advantage o f a null p o i n t in adduction. While excessive occlusion therapy o f the fellow eye c o u l d result in occlusion amblyopia, Lewis 155 has r e p o r t e d that the r e d u c t i o n in visual acuity a n d contrast sensitivity that occurs in the fellow eyes o f children with unilateral cataracts is i n d e p e n d e n t o f the occlusion regimen. T h e y speculated that high spatial f r e q u e n c y channels may require binocular i n p u t in o r d e r to develop normally. Others have also n o t e d a r e d u c t i o n in the visual evoked potential (VEP) amplitudes to pattern reversal stimulation in the fellow eye o f children with unilateral cataracts. 1~6 In contrast, Birch 2a did n o t find any visual deficits in the phakic eyes o f children with unilateral cataracts. T h e visual o u t c o m e is generally better for an eye with an infantile cataract if the fellow eye also has a cataract. However, as m a n y as o n e - q u a r t e r o f child r e n with bilateral infantile-onset cataracts are left legally blind even after t r e a t m e n t (Table 9). Bilateral cataracts are the principal cause o f visual imp a i r m e n t in 1-39% o f school-aged children (Table 10). While infantile cataracts c o n t i n u e to be o n e o f the most c o m m o n causes o f blindness in develo p i n g countries, they are b e c o m i n g a less c o m m o n cause o f blindness in developed countries such as the U n i t e d States. For example, while in 1971, 10% o f the children enrolled in the Western Pennsylvania School for the Blind h a d infantile cataracts, TABLE 9 Visual Outcome with Bilateral Infantile Cataracts

# of

Best Corrected Visual Acuity (%)

Author

Year

Patients

$ 20/ 40

20/5020/100

$ 20/ 200

Gelbart 79 NeumarlnTM Bradford 25 Lorenz159

1982 1993 1994 1994

24 14 23 11

33 78 43 32

42 22 43 46

25 0 14 22

450

Surv Ophthalmol 40 (6) May-June 1996

LAMBERT, DRACK TABLE 10

Prevalence of Congenital Cataracts Among Visually Impaired Children Continent

Country

Prevalence

North America

Canada United States

19% 1-3%

South America

Chile Jamaica Denmark England

9% 39% 5% 8-14%

Netherlands Iceland Ireland Ghana Central African Republic India Thailand Japan Sri Lanka Lebanon Saudi Arabia

17% 26% 5% 15% 14% 7% 17% 24% 17% 15% 18%

Europe

Africa Asia

Middle East

the p e r c e n t a g e h a d d r o p p e d to 1% by 1991 (Table 11). T M This i m p r o v e m e n t can be at least partially attributed to the earlier diagnosis a n d t r e a t m e n t of infantile cataracts. While the diagnosis a n d treatm e n t o f bilateral infantile cataracts is still occasionally delayed in the U n i t e d States (Fig. 26), this is b e c o m i n g rare. U n f o r t u n a t e l y a delay in the diagnosis of infantile cataracts continues to be a major p r o b l e m in m a n y developing countries. Jain us rep o r t e d that in India most children with infantile cataracts do n o t u n d e r g o cataract surgery until they are one to five years o f age, primarily due to a delay in diagnosis. Increased attention needs to be directed worldwide to the screening of all newb o r n s for cataracts a n d to the initiation o f early treatment. B. S T E R E O P S I S

Author Robinson 222 Biglan 19a Drews-Botsch 56a Gilbert 83 Moriarty ls5 Rosenberg 224 Phillips TM Stewart-Brown 252 Schappert 23° Halld~rssen j°° Goggin9t Gilbert 83 Potter 2°9 Gilbert s3 Gilbert TM Tsukahara 26v Eckstein 59" Baghdassarian 14

children for stereopsis who h a d u n d e r g o n e early cataract extraction a n d c o n t a c t lens fitting. Seven (22%) o f these children, five with bilateral cataracts a n d two with unilateral cataracts, demonstrated simultaneous b i n o c u l a r vision w h e n their eyes were aligned with a s y n o p t o p h o r e . They noted, however, that all o f these children h a d strabismus, m a k i n g it unlikely that they would experience stereopsis u n d e r n o r m a l circumstances (Fig. 27). Birch a n d co-workers 21 have also r e p o r t e d gross stereopsis in three children treated for unilateral infantile cataracts. All three were o r t h o t r o p i c a n d two h a d visual acuities of 2 0 / 2 0 in their aphakic eyes. Gregg a n d Parks 9a have r e p o r t e d high grade stereopsis (50 seconds o f arc) in a child with a unilateral cataract who u n d e r w e n t cataract extraction a n d contact lens c o r r e c t i o n d u r i n g the first 24 h o u r s o f life. T h e fellow eye was p a t c h e d for an

Stereopsis continues to be one of the therapeutic goals for children with infantile onset cataracts, but u n f o r t u n a t e l y it has b e e n achieved only rarely (Table i2). Tytla a n d coworkers 268 evaluated 32

TABLE 11 Children Enrolled in the Western Pennsylvania School for Blind Children 19A

School Year

Total Enrollment

Students with Congenital Cataracts

1962-63 1971-72 1981-82 1991-92

199 194 183 180

16 23 12 2

Fig. 26. A child with dense bilateral cataracts. The child was noted to have leukocoria by his mother shortly after birth and nystagmus at three months of age, but was not referred to an ophthalnmlogist until he was 15 months old. Cataract extraction was immediately performed and the child was prescribed aphakic spectacles. Unfortunately, the visual acuity has remained poor in both eyes secondary to amblyopia.

INFANTILE

CATARACTS

451

TABLE 12

Stereopsis Following Monocular Cataract Surgery

Author

Year

# of Patients

Wright 2s3 Gregg96 Birche~ Tytla26s

1992 1992 1993 1993

13 1 14 32

# With Stereopsis (s/arc) $ 60 0 1 0 0

70-400 1 0 3 6

Test Used Randot Randot Randot TLMB*

* TLMB = Tytle-Lewis-Brent stereogram test

increasing n u m b e r o f h o u r s each day until the child was eight m o n t h s of age, after which it was p a t c h e d for eight to ten h o u r s each day until the child was five years old. T h e child was t h e n p a t c h e d for six h o u r s a day until she was eight years old. While this case r e p o r t would suggest that it is possible to achieve high g r a d e stereopsis in children with m o n o c u l a r aphakia, these results should be i n t e r p r e t e d with caution since they evaluated stereopsis with tests that provide m o n o c u l a r clues. Wright 2s3 has a r g u e d that extensive occlusion therapy d u r i n g early infancy disrupts the d e v e l o p m e n t o f binocularity a n d has r e c o m m e n d e d that occlusion t h e r a p y n o t e x c e e d 50% o f an infant's waking h o u r s d u r i n g the first six m o n t h s o f life. In addition to strabismus, a m b l y o p i a a n d excessive occlusion therapy, aniseikonia m a y also disrupt the dev e l o p m e n t of binocularity in unilaterally aphakic children. 67 C. S T R A B I S M U S

Strabismus occurs in a h i g h p e r c e n t a g e of child r e n with either unilateral or bilateral cataracts. France 74 r e p o r t e d that 40% of all children with cataracts have strabismus preoperatively, whereas 71% have strabismus postoperatively. H e n o t e d that 83% of the children with congenital cataracts have an esotropia, whereas 69% of children with acquired cataracts d e v e l o p e d an exotropia. Strabismus has also b e e n r e p o r t e d to be m o r e c o m m o n in children with unilateral t h a n bilateral cataracts? °2 I O L i m p l a n t a t i o n has b e e n r e p o r t e d to reduce the incidence o f strabismus in aphakic child r e n ? sa Strabismus surgery m a y be helpful for imp r o v e d cosmesis, to facilitate contact lens wear a n d to i m p r o v e binocularity. Hiles I°2 has r e c o m m e n d e d p o s t p o n i n g strabismus surgery until the angle o f a l i g n m e n t is stable a n d visual acuity has b e e n optimized. O t h e r s have a d v o c a t e d early strabismus surgery in an a t t e m p t to r e d u c e the n e e d for occlusion therapy. -~H

Fig. 2Z A left esotropia and hypertropia in a five-yearold child who had a dense cataract removed from the left eye when 17 days of age. The child was exceptionally compliant with contact lens wear and occlusion therapy of the fellow eye. The visual acuity is 20/20 in both eyes, but the child has no measurable stereopsis.

D. NYSTAGMUS Nystagmus develops c o m m o n l y in children with dense bilateral cataracts if t r e a t m e n t is delayed. I f cataract surgery is p e r f o r m e d within a m o n t h o f the onset of the nystagmus, the nystagmus will frequently resolve; however, if t r e a t m e n t is delayed l o n g e r than this, the nystagmus will typically persist2 s4 While nystagmus will occasionally develop in children with bilateral cataracts postoperatively, generally, early cataract surgery c o u p l e d with an i m m e d i a t e optical c o r r e c t i o n will p r e v e n t this complication f r o m d e v e l o p i n g 2 5 Less frequently, nystagmus develops in children with unilateral cataracts. Early cataract surgery m a y also p r e v e n t nystagmus f r o m d e v e l o p i n g in these c h i l d r e n 2 44 E. C O S M E S I S

A l t h o u g h cosmesis is a relatively m i n o r consideration c o m p a r e d to visual o u t c o m e in infants with infantile cataracts, it can b e c o m e an i m p o r t a n t consideration in older children with leukocoria. A l t h o u g h the vision o b t a i n e d in an eye with a longstanding infantile cataract will typically be poor, rem o v i n g the cataract may i m p r o v e the a p p e a r a n c e of the eye. Alternatively, a tinted contact lens may be w o r n to cover the white pupil. F. G E N E R A L D E V E L O P M E N T

Visual i m p a i r m e n t is f r e q u e n t l y associated with s o m e d e g r e e o f d e v e l o p m e n t a l delay. Children with bilateral infantile cataracts have b e e n n o t e d to be delayed d e v e l o p m e n t a l l y p r i o r to cataract surgery; however, it has n o t b e e n ascertained if these delays persist after cataract surgery a n d optical correction. O t h e r s have speculated that the extensive occlusion therapy that m a n y children with unilateral congenital cataracts u n d e r g o will be d e t r i m e n t a l to their psychological well-being or d a m a g e their relationship with their p a r e n t s 2 2s,2s6 To d e t e r m i n e if occlusion t h e r a p y caused develo p m e n t a l delay or behavioral p r o b l e m s , Smith 942

452

Surv Ophthalmol 40 (6) May-June 1996

evaluated 22 children with m o n o c u l a r infantile cataracts who h a d b e e n treated with surgery a n d occlusion t h e r a p y a n d c o m p a r e d t h e m to 18 n o r m a l siblings using the M i n n e s o t a Child D e v e l o p m e n t I n v e n t o r y a n d Child Behavior Checklist. T h e y did n o t find any differences b e t w e e n these two groups, suggesting that at least in these areas there does n o t s e e m to be any l o n g t e r m sequelae. Keeffe a n d M a c L e a n ~32 f o u n d t h a t a p h a k i c c h i l d r e n h a v e scores similar to those of n o r m a l children using a standardized n o n v e r b a l ability test, a l t h o u g h their visual m o t o r integration skills were generally below average. VIII.

Summary

Cataracts d u r i n g infancy are b e c o m i n g a less c o m m o n cause of p e r m a n e n t visual i m p a i r m e n t in d e v e l o p e d countries due to earlier detection a n d m o r e effective t r e a t m e n t . Contact lenses c o n t i n u e to be the m o s t frequently used m e t h o d of optically c o r r e c t i n g infantile eyes after cataract surgery, b u t i n t r a o c u l a r lenses are now b e i n g used increasingly, particularly in children with unilateral cataracts. While g o o d visual acuity is b e i n g o b t a i n e d in m o s t infants with bilateral cataracts, children with unilateral cataracts generally have a p o o r visual outc o m e in their aphakic eye. R e c e n t studies have d e m o n s t r a t e d t h a t gross b i n o c u l a r i t y c a n b e achieved in s o m e children with a g o o d visual outcome and orthotropia.

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IV.

V.

VI.

VII.

Outline I. Prevalence II. M o r p h o l o g y A. E m b r y o l o g y B. Specific types 1. Zonular 2. Polar 3. Total 4. M e m b r a n o u s 5. Persistent hyperplastic p r i m a r y vitreous III. Etiology A. G e n e t i c B. Metabolic C. Infectious D. Syndromic E. Prematurity F. T r a u m a

VIII.

G. Laser p h o t o c o a g u l a t i o n H. R a d i a t i o n - i n d u c e d I. Medications J. Idiopathic Work-up A. O c u l a r e x a m i n a t i o n B. L a b o r a t o r y studies C. Pediatric evaluation Management A. Indications for surgery B. Surgery 1. L e n s e c t o m y 2. Primary I O L i m p l a n t a t i o n 3. S e c o n d a r y I O L i m p l a n t a t i o n C. Post-operative complications 1. Amblyopia 2. Posterior capsular opacification 3. S e c o n d a r y m e m b r a n e 4. G l a u c o m a 5. Retinal d e t a c h m e n t 6. E n d o p h t h a l m i t i s 7. Lens reproliferation 8. Post-operative i n f l a m m a t i o n 9. H e m o r r h a g i c r e t i n o p a t h y 10. Cystoid m a c u l a r e d e m a 11. C o r n e a l e d e m a 12. Pupillary abnormalities 13. IOL d e c e n t r a t i o n Visual rehabilitation A. Optical c o r r e c t i o n 1. Contact lenses 2. Spectacles 3. Epikeratoplasty 4. Intraocular lenses B. Amblyopia therapy 1. Animal studies 2. Occlusion therapy 3. P h a r m a c o l o g i c a l penalization Outcomes A. Visual acuity B. Stereopsis C. Strabismus D. Nystagmus E. Cosmesis E General development Summary

Supported in part by NIH grant EY08544, P30 EY06360, and a departmental grant from Research to Prevent Blindness, Inc., New York, New York. The author would like to thank Malia Arrington, Alfreda Florence, and Mary Lynn Covington for their assistance in the preparation of this manuscript, Drs. Lucy Yang, Edward Cotlier, Creig Hoyt, David Taylor, and Jugnoo Rahi for reviewing the manuscript and Alex Deleon for drawing Figure 18. Reprint address: Scott R. Lambert, MD, Emory Eye Center, 1365 Clifton Rd, Atlanta, GA 30322, USA.