Nanophthalmos

Nanophthalmos A Perspective on Identification and Therapy OMAH S. SINGH, MD, RICHARD J. SIMMONS, MD, ROBERT J. BROCKHURST, MD, CLEMENT L. TREMPE, MD

Abstract: Nanophthalmos is a rare and blinding disease. Diagnostic features include a small eye, small cornea, shallow anterior chamber, narrow angle, high lens/eye volume ratio, and uveal effusion. Intraocular surgery has a high rate of disastrous complications and blindness. The 32 eyes (16 patients) presented are in three categories based on angle closure and intraocular pressure levels. Treatment methods included medication, laser iridotomy and gonioplasty, peripheral iridectomy, filtration surgery, and cataract extraction. Glaucoma medication was effective, although miotics sometimes increased pupillary block. Laser iridotomy was successful in 83% of six eyes; laser gonioplasty in 91.6% of 12 eyes. Peripheral iridectomy succeeded in two of seven eyes, and filtering operations provided tension control in two of five eyes. Thirteen of 15 eyes undergoing filtration surgery suffered severe postoperative visual loss. Cataract extraction improved vision in only three of six eyes. The authors' experience confirms that surgery in nanophthalmic eyes has an extremely high complication rate with disastrous results. Medication and laser therapy are the procedures of choice for angle-closure glaucoma in nanophthalmos. [Key words: angle closure, laser gonioplasty, laser iridotomy, microphthalmos, nanophthalmos, uveal effusion, vortex vein decompression.] Ophthalmology 89:1006-1012,1982

Nanophthalmos is a rare, potentially devastating ophthalmic entity frequently unrecognized and, if inappropriately treated, often results in blindness. 1,2 The ophthalmic literature has few guidelines for identification and treatment of this entity. In this report, we outline criteria for identification and offer therapeutic guidelines based on our experience. The anatomic features have been described by several authors,1.3,5,6 and, more recently, attention has been focused on the pathophysiologic mechanisms.1.5,7 From the Glaucoma Consultation Service, Massachusetts Eye and Ear Infirmary and Harvard Medical School, Boston, Massachusetts, and the Eye Research Institute of Retina Foundation Presented at the Eighty-sixth Annual Meeting of the American Academy of Ophthalmology, Atlanta, Georgia, November 1-6,

1981

Reprint requests to Richard J Simmons, MD, 100 Charles River Plaza Boston, MA 02114.

1006

A unique characteristic is the disparity in the proportion of the intraocular components, in which a globular lens of "normal volume" is present in an eye with a very small intraocular volume. 7 This results in a high lens/eye volume ratio (LEVR), "crowding" of the anterior segment, progressive anterior chamber shallowing, narrowing of the angle and eventual angle closure with glaucoma. Treatment of the high incidence of angle closure that complicates this condition varies with the severity of the glaucoma, with no one method of treatment ideal for all stages of the glaucoma. We consider the typical nanophthalmic eye as a small eye with a small cornea, shallow anterior chamber, marked iris convexity, moderate to high hypermetropia, thick sclera, a normal or thick lens with a high lens/eye volume ratio, an extremely high propensity for angle-closure glaucoma, more frequently observed with increasing age, and often complicated by the presence of a thickened choroid, with 0161-6420/82/0900/1006/$1.15

© American Academy of Ophthalmology

SINGH, et al • NANOPHTHALMOS

choroidal and/or nonrhegmatogenous retinal detachment. 8 2.

MATERIALS AND METHODS A series of 32 eyes in 16 patients all referred for evaluation as bilateral nanophthalmos suspects with or without glaucoma are presented herein. The following ocular parameters were measured when possible, and the diagnosis was made based on the presence of characteristic anatomic features and clinical course: (A) Age and sex of patient, (B) corneal diameter, (C) anterior chamber depth, (D) iris configuration, (E) width of anterior chamber angle, (F) refractive error, (G) axial length, (H) lens size, (I) intraocular pressure, (J) amplitude of the ocular pulse, and (K) glaucoma status. Each eye was placed into one of three categories according to the glaucoma status based on the appearance of the angle and the intraocular pressure. The angle was described verbally according to Chandler and Grant and by numerical grades 9 according to Shaffer. Category I. Angle completely open gonioscopically, with marked iris convexity (Shaffer Grade 1-2), and normal tension ~20 mm Hg. Category II. The angle partially closed (Shaffer Grade 0-1), with tension ~ 20 mm Hg. Category III. The angle partially or totally closed (Shaffer Grade 0-1), with tension >20 mm Hg. METHODS OF TREATMENT

Frequent observation was a key factor, the frequency of examination determined by the angle configuration and the degree of closure on gonioscopy. In all nan ophthalmic eyes we used the following two surgical techniques before surgery. Operative gonioscopy and anterior chamber deepening. To determine the extent of synechial angle closure and the glaucoma operation most likely to succeed. 10 Operative sclerotomy. To drain the suprachoroidal space of any fluid that might pre-exist or appear during surgery. Three forms of treatment used were: Medical therapy. Included glaucoma medications and sometimes systemic steroids. Laser surgical procedures. 1. Laser iridotomy. Was the initial procedure of choice used to treat eyes with pupillary block, subacute angle closure, and acute angle closure. 2. Laser gonioplasty 11. Laser was applied to the peripheral iris to specifically widen an angle which showed symptomless chronic narrowing or appositional closure. Operative surgical procedures. 1. Vortex vein decompression. Brockhurst has

3.

4.

5.

shown recently that this technique is successful in treatment of uveal effusion in the nanophthalmic eye. 8 Peripheral iridectomy. Performed in the manner reported by Chandler. 12 Glaucoma filtration procedure. These were chosen by evaluation of preoperative glaucoma control (on maximum tolerated medical therapy), extent of open angle on preoperative gonioscopy and on the chamber deepening pTocedure with operative gonioscopy, 9 the outflow facility by tonography, and the pressure control desired after surgery. Cataract extraction. The surgical indications were the same as for ordinary eyes, but surgery was performed with additional preoperative precautions, including hyperosmotics and preoperative sclerotomies. Anterior vitrectomy (VISe method) was combined with cataract extraction in some cases. Cyclocryotherapy. This therapy was used mainly in eyes with poor visual acuity.

DEFINITIONS

The terms "success," "failure," and "stability," used in this study, refer to the results of therapy on glaucoma control and are defined as follows: Success. Glaucoma control and prevention of further angle closure. Failure. For laser iridotomy, no visible patent iris hole; for laser gonioplasty, failure to achieve widening of the angle treated; and for surgery, failure of glaucoma control and/or blindness. Stable. Refers to glaucoma control and prevention of progressive angle narrowing.

RESULTS The results of analysis of the data are presented in three broad categories: (1) patient data, (2) ocular parameters, and (3) results of therapy. Patient data (Table 1). 1. Sex. The ratio of males to females was 7 to 9. 2. Age. In this series, the average age of the patient when first seen by us was 52.8 years (range 19-69 years). Ocular parameters 3 ,14 (Table 1). Corneal diameter. In 26 eyes, the average external horizontal corneal diameter was small-l0.30 mm (median 10.50 mm, range 9.50-11.0 mm). Anterior chamber depth. In 28 eyes, the average anterior chamber depth was 1.46 mm (median 1.43 mm, range <1-2.70 mm). The anterior chamber depth was definitely shallower in nanophthalmos. Iris configuration. All 32 eyes had marked iris convexity, and iridocorneal touch was present in 14 eyes at our initial examination. 1007

OPHTHALMOLOGY • SEPTEMBER 1982 • VOLUME 89 • NUMBER 9

Table 1. Ocular Parameters Ocular Parameter

No. Eyes

Nanophthalmos

Sex

32 eyes (16 pts)

Men-14 eyes (7 pts) Women-18 eyes (9 pts)

Age

32 eyes (16 pts)

Average 52.8 yrs median 56 yrs (range 19-69 yrs)

Corneal diameter

26 eyes (13 pts)

Average 10.3 mm median 10.50 mm (range 9.50-11.00 mm)

Anterior chamber depth

28 eyes (15 pts)

Average 1.46 mm median 1.43 mm (range 1-2.70 mm)

Refractive error

32 eyes (16 pts)

Average +13.600 median +13.84 (range +7.25- +20.0)

Axial length

28 eyes (16 pts)

Average 17.00 mm median 16.8 mm (range 14.5-20.5 mm)

Anteroposterior lens thickness

22 eyes (12 pts)

Average 5.18 mm median 5.19 mm (range 4.20-7.26 mm)

Lens/eye volume ratio

22 eyes (12 pts)

Average 12.16% median 11.75% (range 4%-25%)

Sclera and choroid combined thickness

14 eyes (8 pts)

Average 2.78 mm median 3.0 mm (range 0.75-4.0 mm)

Refractive error. All 32 eyes in this series were hypermetropic with an average refractive error of + 13.60 diopters (median + 13.84 diopters, range +7.25 to +20.00 diopters). Axial length (Internal sagittal diameter). The internal sagittal diameter as measured with ultrasound Bscan in 28 eyes was short in all eyes, with an average axial length of 17.00 mm (median 16.8 mm, range 14.50 mm to 20.50 mm). (All ultrasound measurements were made by Dr. C. Trempe). Lens thickness. The average anterior-posterior lens thickness in 22 eyes as measured by ultrasound was 5.18 mm (median 5.19 mm, range 4.20-7.26 mm). In nanophthalmic eyes, ultrasound measurements confirmed that nanophthamic lenses were thicker, but more globular in shape with a "normal" lens volume. Lens/eye volume ratio (LEVR) 7. In 22 eyes (12 patients), the average LEVR calculated from ultrasound measurements was abnormally high: average 12.16% (median 11.75%, range 4-25%). Combined thickness of sclera and choroid. In 28 eyes (15 patients) analyzed with ultrasound, all eyes had thicker than normal sclera and choroid. In 14 eyes (8 patients) on which the combined thickness was 1008

measurable, the average combined thickness was 2.78 mm (median 3.0 mm, range 0.75-4.0 mm). Pre-operative retinal and/or chorodial detachment. Of 28 eyes evaluated with ultrasound and indirect ophthalmoscopy, 11 eyes had preoperative spontaneously occurring choroidal detachments, five of which were associated with nonrhegmatogenous retinal detachment. Two other eyes had detectable retinal detachment without choridal detachment. Classification by glaucoma status. The eyes were all categorized by glaucoma status as defined above. Category I: 10 eyes (7 patients); Category ll: 4 eyes (3 patients); and Category Ill: 18 eyes (11 patients). Results of therapy. The success of different treatment methods was analyzed to develop our therapeutic recommendations based on the methods that proved to be most successful in each glaucoma status category. OBSERVATION

The ten eyes in Category I were observed at frequent and regular intervals, and in all eyes, there was a definite tendency for progressive narrowing of the angles with 2/10 eyes (20% eyes), showing progression from Category I to Category II. Upon progressing to Category II, one of these eyes was treated with laser iridotomy and the other with laser gonioplasty, and both eyes have maintained open angles following laser therapy for 6 months and 20 months, respectively. MEDICAL THERAPY

The full spectrum of glaucoma medication was used. Miotics. Miotics were used in 17 eyes (ten patients) with a variable response. Pilocarpine was the miotic most commonly used (15 eyes). In most eyes, miotics produced widening of the angle and decreased intraocular pressure. In a few eyes, miotics produced visible shallowing of the anterior chamber with increased pupillary block,13 which was relieved by discontinuing miotics. Epinephrine and Timoptic. Epinephrine and Timoptic were used in a total of eight eyes (five patients), with some slight improvement in pressure. In no instance was the angle closure or glaucoma control worsened. Carbonic anhydrase inhibitors. These were used in 11 eyes (six patients)-Neptazane in four eyes (two patients) and Diamox in seven eyes (four patients). The carbonic anhydrase inhibitors were generally effective in decreasing intraocular pressure, and in One eye, the angle was actually wider two hours after treatment with Diamox. In no instance, did they aggravate tension control. Hyperosmotics. Hyperosmotics were effective in short-term intraocular pressure control in acute angle closure glaucoma or before surgery. Systemic steroids. These were used in two eyes of two patients to treat preoperative uveal effusion and

SINGH, et al • NANOPHTHALMOS

retinal detachment, and in both eyes the effusions improved. LASER THERAPY

Laser iridotomy (Table 2). This was used as the initial procedure of choice in six eyes (four patients). A total of 12 iridotomies were performed in these six eyes-one eye was in Category I and five eyes in Category III. In the eye in Category I, one laser iridotomy was performed when there was progression from an open angle (Category I) to partial angle closure (Cate.gory 11). In the five eyes in Category III, a total of 11 laser iridotomies were performed, with four of these five eyes requiring mUltiple treatments to produce and/or maintain patent iridotomies. Patency was achieved in 9/11 iridotomies at the initial treatment. In one of the unsuccessful iridotomies (done in 1977), the laser used had insufficient power and although iris perforation was not achieved, the gonioplasty effect flattened the iris, widened the angle, and resulted in decreased intraocular pressure. The other failure of laser iridotomy was in an eye with extensive posterior synechia and pupillary block. Although patency was not achieved, the gonioplasty effect provided improvement in pressure for 20 months; eventually, pupillary block developed, and when this failed to respond to laser therapy, surgery was performed. Postoperative complications ensued, and the eye eventually became blind and phthisical. Of the 12 laser iridotomies performed (six eyes of four patients), 10 out of 12 (83%) remained open for an average follow-up time of 44.1 months (range 6-66 months). Prelaser therapy, all six eyes required glaucoma medications to achieve good pressure control; postlaser, only four eyes required the same medication, one eye required less medication, and one eye required no medication.

Table 3. Laser Gonioplasty No Eyes No. of with Cate- No Treatment Widened gory Eyes Sessions Angle

3

7

8

15

12

23

III

Total

Improved TenSion FollOWing Laser

1 eye (-1 mm) 3 eyes 3 Average 10 7 mm (range: -6 to -19mm) 7/8 8 eyes (average -10 4 mm range: -1 to -38 mm) 11/12 12112 eyes

Follow-up Time

Compl!cations

15 mos

None

Average 30 mos (range' 946 mos)

None

Average 41 mos (range: 1862 mos)

None

closure. Eleven of 12 eyes (91.6%) had successful widening of the angle, and all 12 eyes had decreased tension following gonioplasty. SURGERY

Laser gonioplasty (Table 3). This was used when there was evidence of progressive narrowing and chronic symptomless closure of only a portion of the angle. In cases with acute or subacute angle closure, where all or almost all of the angle was closed, laser iridotomy was attempted as the initial procedure. Laser gonioplasty was used as the initial procedure of choice in 12 eyes (eight patients). The 12 eyes received a total of 23 gonioplasty treatments, and at each treatment session, a variable number of spots were applied according to the amount of angle

Peripheral iridectomy (Table 4). Peripheral iridectomy was performed on seven eyes-one eye was classified as Category II, six eyes as Category III. The one eye in Category II was the fellow eye of a patient who presented with an acute angle-closure glaucoma attack. Prophylactic peripheral iridectomy was performed on this eye and was successful. In Category III, only one eye showed a successful result with a patent iridectomy and tension controlled on medications. The other five eyes all had complicated courses resulting in decreased vision or blindness after surgery (Table 5). Filtration surgery. Primary fIltration surgery was performed on five eyes (four patients) all of which were classified as Category III (Table 6). Trabeculectomy. Trabeculectomy was performed on two eyes (two patients). In one eye, the angle was closed 360 and previous peripheral iridectomy had failed. Following trabeculectomy, the eye continued to do well off medication for 29 months, with pressures controlled and nonprogressive visual field loss. In the second eye, treatment with laser iridotomy and gonioplasty had maintained an open angle with good pressure control for 20 months. The eye eventually developed angle closure glaucoma with a choroidal detachment. This eye failed to respond to medical and laser therapy, and, therefore, filtration surgery was performed. This was followed by increased choroidal detachment, retinal detachment, and failure of filtra-

Table 2. Laser Iridotomy

Table 4. Peripheral Iridectomy

0

,

No. of Category Eyes

Total no. Iridotomies

Patent Hole at Initial Rx

Average Follow-up Time 6 mos

III

5* (4 pts)

11*

* Failure-one eye-2!11 iridotomles.

9/11 (82%)

49.5 mos (range 18-66 mos)

No. Eyes

Success Tension Control

Success Retain Pre-op Vision

Follow-up Time

II

1

1 eye

1 eye

18 yrs, 4 mos

III Total

6 7

1/6 eyes 2/7 eyes

1/6 eyes 2/7 eyes

Category

36 mos

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OPHTHALMOLOGY • SEPTEMBER 1982 • VOLUME 89 • NUMBER 9

Table 5. Peripheral Iridectomy-Failures Cause of Failure Following Surgery

No. of Eyes

Retinal detachment Flat anterior chamber Malignant glaucoma Flat anterior chamber Tension uncontrolled Flat anterior chamber

Preop VA

Postop VA

20/30 20/200 CF 6'

LP HM CF 6'

20/60 20/60

20/100 20170

Table 6. Primary Glaucoma Filtration Category

No. Eyes

III

2

Total

3 5

Procedures

Success (Tension Control)

Follow-up

1 eye

29 mos

1 eye 2/5 eyes

18 yrs

Trabeculectomy Full thickness (conventional)

tion (Table 7). The fellow eye in this patient was blind from complications following a previous surgical peripheral iridectomy. Conventional filtering operations with a fullthickness sclerostomy. Conventional (full-thickness sclerostomy) filtering operations were performed in three eyes of two patients (Table 6). Surgery was successful in one of these with good postoperative tension control on no glaucoma medication for a follow-up of 18 years. The other two filtering operations (two eyes) failed (Tables 7, 8). One eye developed bleb failure within one month after surgery and required two subsequent treatments with cyclocryotherapy before tension was controlled. In the second eye, during the 24 hours following surgery, there was massive exudative retinal

and choroidal detachment with dislocation of the lens through the sclerostomy into the bleb. There was gradual bleb failure over the following five months. Subsequent bleb revision and lens removal resulted in pressure control. Glaucoma filter reoperations were done on three eyes (two patients). Cataract extraction. Cataract extraction was performed on six eyes of four patients: one eye was in Category II. five eyes in Category III (Table 9) using the following techniques: 1. Intracapsular cryophake cataract extraction: three eyes (two patients). 2. ICCE from below in the presence of a filtering bleb above: two eyes (two patients). 3. Lensectomy and anterior vitrectomy with vitreous infusion clltting instruments (VICS): one eye.

Of these six eyes, cataract surgery was successful in 50% (three out of six eyes), with improved vision after surgery. The other three eyes developed complications resulting in loss of useful vision in all three eyes (Table 9). Vortex vein decompression. Vortex vein decompression has thus far been used in four eyes (three patients) with preoperative uveal effusion and/or retinal detachment. One of us (RJB) has been the surgeon for all four ofthese eyes. In one of these eyes in which this was done prophylactically for preoperative spontaneous choroidal effusion, the effusion resolved and was followed by successful cataract extraction several months later.

DISCUSSION Nanophthalmic eyes represent a spectrum in which recognition of the cardinal signs is of prime importance. Some of the clues include a very small eye, high hyperopia with thick aphakic-style glasses in aphakic patient, a family history of angle-closure glaucoma or blindness, a blind fellow eye following previous intraocular surgery, a short axial length, shallow anterior

Table 7. Failure of Glaucoma Filtration Category

No. Eyes

III

Indications for Surgery

Operation

Pupillary block

Trabeculectomy & 2 sclerotomies

Angle-closure glaucoma Angle-closure glaucoma Total

1010

3 eyes

Trephine Sclerectomy filter

Postop Complications Flat AC V 20/20CHLP Tension uncontrolled Bleb scarring, large choroidals, tension uncontrolled Chor. & retinal detachment, dislocated lens into bleb, tension uncontrolled, failed bleb

SINGH, et al • NANOPHTHALMOS

Table 8. Glaucoma Filter Reoperations No. Eyes

Category

Results (Tension)

Procedures

III

Sclerotomy & choroidal tap, closed vitrectomy, anterior chamber reformation Bleb revision and subconj. lens removal 2 cryotreatments -over 6 mos

Total

3 eyes

Fail Flat AC, mature cataract Phthisis (V20/20D-LP) Success Tension controlled Follow-up 36 mos Success Tension controlled Follow-up 36 mos Success 2/3 eyes

Table 9. Cataract Surgery

Category

Previous Ocular Surgery

No. Eyes

Success Visual Improvement

Operative Procedure

Success Maintain Preop Tension Control

Follow-up

II

Peripheral Iridectomy

Intracapsular extraction cataract

Yes

Yes

9 yrs

III

Glaucoma filter

Cataract from below Intracapsular extraction cataract

Yes

Yes

11 mos

Yes

Yes

24 mos

Intracapsular extraction cataract Cataract from below Lensectomy, anterior vitrectomy

No-retinal detachment No-corneal edema No

No

<10 mos

Yes

<1 mo

No-phthisis

<3 mos

Vortex vein decompression No Glaucoma filter

Total

6

2 glaucoma operations 5/6 eyes (83%)

3/6 eyes (50%)

Table 10. Summary of Filtration Surgery Procedure Penpherallrldectomy Primary glaucoma filtration Glaucoma filter reoperallons Total

No. Eyes

Success Tension Control

Success Retain Preop Vision

7

2/7 eyes

2J7 eyes

5

2/5 eyes

3 15

2/3 eyes 6/15 eyes

oeyes oeyes 2J15 eyes

chamber, marked iris convexity, and narrow angles. The effectiveness of therapy is related to the stage at which the disease is treated. In Category I, where the angle is open completely with a typical markedly convex iris configuration, frequent observation is important. In most of these eyes, the angles show increasing narrowing with progressive appositional closure and concomitant glaucoma. Early in the disease, laser combined with medical therapy is most effective in widening the angle, relieving pupil-

4/6 eyes (66.6%)

lary block, and retarding or preventing appositional or synechial closure that results in eventual angle-closure glaucoma. In Category III, with angle closure (appositional or synechial) and glaucoma, medical therapy is imperative. Miotics generally widen the angle, although the response is variable,3,13 and in three eyes in this series, they increased the pupillary block. Carbonic anhydrase inhibitors, topical timolol and epinephrine, are useful, and in no eye did they worsen the glaucoma. Laser therapy is very valuable, and when effective, delays the need for surgery with its high incidence of complications in these eyes. Our current recommendation is for frequent .observation. When the angle shows progressive narrowing or localized appositional closure, gonioplasty is indicated. Gonioplasty requires low energy levels and is benign. If the area of closure is broad, or if pupillary block or acute angle closure is present, then laser iridotomy should be tried. When successful, this relieves pupillary block and almost always has a com-

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OPHTHALMOLOGY. SEPTEMBER 1982 • VOLUME 89 • NUMBER 9

bined gonioplasty effect producing widening of the angle when appositional or even early synechial closure is present. When intraocular surgery is inevitable, precautionary measures should be undertaken to minimize potential complications. If preoperative choroidal effusion is present, systemic steroids and vortex vein decompression may provide additional safeguards. Operative sclerotomies release suprachoroidal fluid, especially if there is ultrasound or clinical evidence of choroidal detachment before surgery. N anophthalmic eyes respond disastrously to intraocular surgery with a high incidence of postoperative complications. Table 10 clearly illustrates this. Of the total 15 eyes on which any type of glaucoma surgery was performed, 9/15 eyes (60%) failed to achieve tension control, 13/15 eyes (86.6%) suffered visual loss following surgery, and in six of these 13 eyes, visual acuity fell to counting fingers at 6 ft or less. Only two eyes (13.3%) retained preoperative vision. The complications leading to severe postoperative visual loss in these 13 eyes include: malignant glaucoma-one eye; retinal and choroidal detachment-three eyes; and prolonged flat anterior chamber-six eyes. Of these 13 eyes, nine had dense cataracts, five of these developing rapidly after postoperative flat anterior chamber. Lens removal relieves the anterior chamber crowding resulting from lens thickening and, theoretically, could be considered as an option for prophylaxis. Since intraocular surgery has such a poor prognosis, this approach currently is too risky, except as a therapeutic option for the most advanced stages of nanophthalmos with glaucoma. In this series, some patients have documented family histories of blindness from angle-closure glaucoma, and provide additional support to existing documented pedigrees of autosomal recessive and dominant inheritance patterns in nanophthalmos. 3 ,7,8 The response of one eye to previous surgery is a strong indicator of prognosis and potential postoperative complications of the fellow eye. One interesting feature is the wide ocular pulse observed in the nanophthalmic eye that may have an amplitude of as great as 8-12 mm Hg. In this series, 11 eyes (six patients) showed a wide ocular pulse (8-12 mm Hg). In five aphakic eyes, the ocular pulse fluctuation was still present after surgery, and in two of these patients with unilateral aphakia, the ocular pulse measured the same in the phakic as in the fellow aphakic eye. This phenomenon may be related to choroidal engorgement and abnormal intraocular hemodynamics caused by vortex vein compression due to thickened inelastic sclera as postulated by one of us. 8

1012

We recommend in cases of narrow angle glaucoma that the diagnosis of nanophthalmos be entertained with full evaluation of all ocular parameters whenever possible. Noninvasive therapy should be used early and when intraocular surgery is inevitable, the surgeon should use extensive preoperative precautions prior to entering the eye.

ACKNOWLEDGMENTS The authors wish to express their gratitude to Paul A. Chandler, MD, and W. Morton Grant, MD, for reviewing the manuscript and their valuable advice; T. M. Richardson, MD, kindly provided information on three of these cases. Samuel Douglas and Ruthanne B. Simmons provided valuable assistance in chart research.

REFERENCES Calhoun FP, Jr. The management of glaucoma in nanophthalmos Trans Am Ophthalmol Soc 1975, 73:97-119. 2. O'Grady RB Nanophthalmos Am J Ophthalmol 1971, 71'

1251-3 3 Duke-Elder S, ed System of Ophthalmology, Vol 3, pt 2: Normal and Abnormal Development Congenital deformities. St LOUIS: CV Mosby, 1964, 488-95 4 Zamorani G. Microftalmo e glaucoma. Boll Oculist 1960;

39'746-57 5. Brockhurst RJ. Nanophthalmos with uveal effUSion: a new clinical entity. Trans Am Ophthalmol Soc 1974, 72:371-403. Also Arch Ophthalmol 1975, 93: 1289-99 6. Cross HE, Yoder F Familial Nanophthalmos Am J Ophthalmol

1976, 81'300-6 7. Kimbrough RL, Trempe CS, Brockhurst RJ, Simmons RJ Angleclosure glaucoma In nanophthalmos Am J Ophthalmol 1979;

88572-9 8 Brockhurst RJ. Vortex vein decompression for nanophthalmlc uveal effusion. Arch Ophthalmol 1980; 98'1987-90 9 Herlck WV, Shaffer RN, Schwartz A. Estimation of Width of angle of anterior chamber InCidence and significance of narrow angle Am J Ophthalmol 1969; 68626-9 10 Chandler PA, Simmons RJ Anterior chamber deepening for gonioscopy at time of surgery Arch Ophthalmol 1965,

74.177-90. 11. Simmons RJ, Kimbrough RL, Belcher CD, Dullt RA Laser gonioplasty for speCial problems In angle closure glaucoma. In Symposium on Glaucoma, Transactions of the New Orleans Academy of Ophthalmology St Louis CV Mosby 1981,

220-35 12 Chandler PA, Grant WM Lectures on Glaucoma. Philadelphia: Lea and Febiger, 1965; 381-7 13 Wilkie J, Drance SM, Schulzer M The effects of miotlcs on anterior chamber depth Am J Ophthalmol 1969; 68:78-83 14 Wilmer HA, Scammon RE Growth of the components of the human eyeball I. Diagrams, calculations, computations and reference tables Arch Ophthalmol 1950, 43:599-619.