Long-term results of intraocular lens implantation in pediatric patients

Long-term results of intraocular lens implantation in pediatric patients Robert M. Sinskey, M.D., Juan O. Stoppel, M.D., Pranav Amin, M.D.

ABSTRACT Between 1980 and 1990,42 eyes of 34 patients (age range: 18 months to 18 years) were implanted with an intraocular lens, with 29 being primary implantations and 13 secondary. The primary implantation group comprised patients with congenital, developmental, and traumatic cataracts. Patients in the developmental and traumatic cataract groups achieved the best visual acuity. Those with congenital cataracts had the poorest visual outcome. Follow-up ranged from a minimum of three months to more than ten years. Overall the patients demonstrated an improvement in visual acuity and the psychological advantage of enhanced visual function without spectacles or contact lenses. We conclude that with proper case selection and a controlled, skilled surgical approach, the use of an intraocular lens for visual rehabilitation in the pediatric age group is a feasible approach. Key Words: intraocular lens, pediatric cataracts, primary capsulotomy, secondary intraocular lens

Managing cataracts in the pediatric age group is challenging and controversial in young children with unilateral cataracts where the risk of irreversible amblyopia is present. 1-3 Visual prognosis varies depending on the degree of the lens opacity, the patient's age,4.5 and whether the condition is unilateral or bilateral. 6 Visual rehabilitation of these patients can be done with spectacles, contact lenses,7-9 epikeratophakia,9 or intraocular lenses (IOLs). Choyce,1O using an anterior chamber lens, implanted the first JOL into a child's eye in 1955. In 1959 Binkhorst implanted an iridocapsular fixated lOL.l I Advances in IOL manufacturing and in surgical techniques have made possible IOL implantation in young children. 12-20 This article presents the results of primary and secondary IOL implantation in pediatric eyes followed over a long period and describes the surgical principles involved.

SUBJECfS AND METHODS Between 1980 and 1990, 42 IOLs were implanted in 34 children's eyes. Twenty-nine (69%) were primary implants and 13 (31%) were secondary. Of those with primary implants ten patients (34%) had congenital cataracts, II (38%) had developmental cataracts, and eight (28 %) had traumatic cataracts. Age at the time of surgery ranged from 18 months to 18 years. Informed consent

was obtained from each child's parents before treatment. Parents were advised of the risks, benefits, and alternatives as part of the consent procedure. FDA approval, required for IOL implantation in patients 18 years old or younger, was obtained. All patients had an ultrasound study, axial length measurement, and keratometry readings. Children too young to have A-scan, ultrasonography, and keratometry while awake received general anesthesia for the procedures. Pupils were pharmacologically dilated and a Terry keratometer was used to measure corneal curvature. An A-scan unit measured the eye's axial length. At various times during the ten-year period, IOL power was calculated with the Binkhorst, SRK, or SRK-T formula. Based on Gordon and Donzis'21 finding that the greatest changes in axial length and keratometry readings occur during the first 18 months of life, we aimed to achieve emmetropia in most of our patients because only children 18 months or older had implants. Two hours before surgery pupils were dilated with one drop each of I % cyclopentolate hydrochloride and 2.25% phenylephrine hydrochloride. A fornix-based conjunctival flap was made with a 6.0 mm scleral incision 1.5 mm from the limbus. The anterior chamber was entered with a 3.25 mm keratome and filled with sodium hyaluronate 1.2%. A central anterior capsulotomy 4 mm to 6 mm in diameter was made

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California 90404-0031 . 405

with a cystotome. The lens material was removed by irrigation and aspiration (1/A). When the lens nucleus was too firm to be removed by II A, an ultrasonic tip was used. The 3.25 mm incision was enlarged to 6.0 mm and a three-piece Sinskey-style IOL with a 6.0 mm poly(methyl methacrylate) (PMMA) optic, polypropylene loops, and an overall diameter of 13.5 or 14.0 mm was implanted under sodium hyaluronate 1.2%. The IOL was placed in the capsular bag when possible in primary cases and in the ciliary sulcus in secondary implantations. Residual plaques on the posterior capsule were removed under viscoelastic after the IOL was placed by teasing it with a 30-gauge bent needle. If the posterior capsule was inadvertently opened during plaque removal, the IOL and the viscoelastic kept the vitreous from migrating anteriorly around the IOL. If the child was too young to cooperate during a postoperative neodymium:Y AG (Nd:Y AG) capsulotomy, a primary posterior caps ulotomy was done with a 30-gauge bent needle under viscoelastic after IOL implantation. The wound was closed with a shoelace 9-0 nylon suture. Betamethasone sodium phosphate and betamethasone acetate suspension (Celestone® Soluspan®) and cefazolin sodium (Cephalosporin®) were injected into the inferior subconjunctival space. A shield was put in place with tape but no eye pad was used. Postoperatively a topical antibiotic steroid combination, tobramycin 0.3% and dexamethasone 0.1 % (TobraDex®), was prescribed four times a day for three days. Subsequently, prednisolone acetate drops were used four times a day for at least one month. To avoid posterior synechial formation, a short-acting mydriatic (tropicamide 1%) was given twice a day. It was extremely important to watch the parents instill the drops into the child's eye to ensure the medication was delivered adequately. Patients in the pediatric age group require frequent follow-up examinations since low-grade inflammation and pupillary membrane formation are common unless reasonably high levels of steroids are maintained. Systemic steroids were used occasionally in consultation with a pediatrician if topical steroids failed to control inflammation adequately.

RESULTS Forty-two IOLs were implanted in 34 children's eyes between 1980 and 1990. Twenty-nine (69%) were primary implants and 13 (31 %) were secondary. The distribution of cataracts by type and patient age is shown in Table I. Age at the time of surgery ranged from 18 months to 18 years (average = 8.78 years). The developmental cataract and secondary implantation groups had the best visual outcome followed by the traumatic group, with worst results in the congenital group. Ta406

Table 1. Distribution of cataracts by type and patient age. Age (Years)

Eyes Cataract Type

n

(%)

Range

Average

Congenital

\0

(34)

1.5-12

6.25

Developmental

II

(38)

3.0-16

8.72

8

(28)

1.0-17

11.30

Traumatic

Table 2. Preoperative and postoperative visual acuity in developmental cataracts. Visual Acuity Patient

Preoperative

Postoperati ve

I

FC

20/25

2

HM HM

20/30

LP

20/100 LP

5

20/100

20/20

6 7

FC

20/30

FC

8

HM

20/25 FC

9

FC

to 11

20/60 20/400

3 4

20/30 20/25 20/25

Table 3. Preoperative and postoperative visual acuity in traumatic cataracts. Visual Acuity Patient

Preoperative

Postoperative

1

20/400

20/25

2 3 4

HM

20/30 20/30 FC

5 6 7

20/200 FC

20/20 FC 20/400

8

20/100

20/20

FC

HM HM

bles 2 through 5 list the preoperative and postoperative visual acuity of the developmental, traumatic, congenital, and secondary implantation groups, respectively. Ofthe 11 patients with developmental cataracts, eight (73%) achieved a visual acuity of 20/40 or. better, one (9%) achieved 20/100 to 20/200, and three (18%) achieved 20/400 or worse. Average age was 8.72 years. Of the eight patients with traumatic cataracts, five (62.5 %) had a postoperative visual acuity of 20/40 or better and three (37.5%) achieved 20/400 or worse. Average age was 11. 3 years. The congenital cataract group comprised ten patients, one (10%) who achieved 20/40 visual acuity, one

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Table 4. Preoperative and postoperative visual acuity in congenital cataracts.

DISCUSSION

Over the past 30 years, the surgical management of congenital and developmental cataracts has evolved Patient from a simple discission of the lens allowing the lens material to absorb to linear extraction22 to pars plana 20/40 1 20/80 lensectomy and anterior vitrectomy. These techniques 20/400 HM 2 are still in use in many countries. In the past ten years, 20/400 HM 3 pars plana lensectomy and anterior vitrectomy23 seems 20/80 Fe 4 to have been the most popular procedure among pediFe 20/400 5 atric ophthalmologists in the United States. This proFe LP 6 cedure requires either an aphakic spectacle or contact lenses for visual rehabilitation. Fe LP 7 The use of IOLs to treat unilateral cataracts or bilatLP 20/400 8 eral cataracts in pediatric patients is controversial. Many Fe HM 9 papers have reported the visual outcome and compliFe HM 10 cations in these patients. 10-20.24,25 Improvements in instrumentation and surgical techniques have allowed many of these patients to achieve good visual acuity Table 5. Preoperative and postoperative visual acuity in second- without the psychological trauma caused by the need to ary implants. use contact lenses or aphakic spectacles. 14,18 The visual outcomes in our series are similar to those Visual Acuity published by Dahan and Salmenson. 24 In the primary Postoperative Patient Preoperative implant group, the eyes with developmental and traumatic cataracts achieved the best visual acuity since 20/400 1 LP these patients did not have profound pre-existing ambly20/30 2 20/200 opia. In the unilateral congenital cataract group the vi20/40 3 20/200 sual outcome was poor because of the profound degree 20/15 4 20/20 of amblyopia resulting from lack of visual stimulation Fe 20/30 5 early in the child's development. These patients had 20/30 6 20/25 delayed surgery (average age 6.25 years old). We agree with Cheng and coauthors5 that surgery should be done 20/400 Fe 7 earlier for better results. In the secondary implantgroup 20/20 8 20/20 the visual results were good; 70% had a visual acuity of 20/80 20/50 9 20/40 or better. 20/30 10 20/40 In this pediatric population posterior capsule opaci20/30 11 20/400 fication is often seen soon after surgery. We performed 20/50 12 20/200 a primary capsulotomy after IOL implantation in patients not old enough to cooperate with an Nd:YAG 20/20 13 20/25 laser capsulotomy postoperatively. If the patient was old enough to cooperate, the capsulotomy was performed (10%) between 20/60 and 20/80, and eight (80%) when the opacification appeared after surgery. We believe that if the surgeon does not implant an IOL at the 20/400 or worse. Average age was 6.25 years. In the secondary implantation group of 13 patients, time of the primary surgery he or she should be careful nine patients (70%) had a postoperative visual acuity of to leave some posterior capsule after the capsulotomy 20/40 or better, two (15%) 20/60 to 20/80, two (15%) and vitrectomy to preserve the option of secondary im20/400 or worse. Average age was 11.3 years (range 15 plantation of a posterior chamber IOL. Removing most of the posterior capsule during the initial cataract surto 18 years). Follow-up ranged from three months to more than gery reduces the number of IOL types that can be implanted later. ten years (average 3.24 years). At present, anterior chamber lenses carry a higher Postoperative complications were confined to the secondary implant group. One patient (#1) had a retinal complication rate than the posterior chamber lenses imdetachment, and two (#7 and #10) required an addi- planted in the bag or sulcus. Children in particular are tional procedure to remove residual cortex released prone to ocular trauma and are more likely to rub the when adhesions between the iris and capsule were lysed. eye, increasing the possibility of secondary complicaIn two patients of the same group (#6 and #9), we sus- tions. It is still too early to assess the long-term safety of pected that cystoid macular edema caused reduction in scleral fixated posterior chamber IOLs, so this procedure is probably not an alternative in children at this time. visual acuity. Visual Acuity Postoperative Preoperative

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In all of our patients we implanted a three-piece Sinskey-style IOL with a 6.0 mm PMMA optic, polypropylene loops, and overall diameter of 13.5 mm or 14.0 mm. Some authors report that lenses with polypropylene loops might not be biologically inert,26,27 although we have not encountered any problems with this lens. A lens with polypropylene loops is more flexible than a one-piece PMMA lens. This flexibility can be beneficial in implantation in children. We aimed to achieve emmetropia in developmental and traumatic cataracts and in secondary implantations. The average age at the time of surgery was 8.72 years, 11.3 years, and 9 years, respectively. We aimed for undercorrection in congenital cataracts because of the expected growth of the eye. 28 (The younger the patient, the more undercorrection was sought.) In conclusion, primary and secondary implantation should be considered an option in managing pediatric cataracts. Primary capsulotomy under viscoelastic after IOL implantation should be performed in children too young to cooperate during a postoperative Nd:YAG capsulotomy. If a primary IOL implantation is not possible, the surgeon should try to leave enough posterior capsule for a secondary posterior chamber IOL implantation.

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