Vitrectomy

Glaucoma after Pediatric LensectomyjVitrectomy JOHN w. SIMON, MD,t NALIN MEHTA, MD,t STEVEN T. SIMMONS, MD,t ROBERT A. CATALANO, MD,t LLOYD L. LININGER, PhD2

Abstract: Glaucoma after pediatric cataract surgery, once well recognized, now occurs only rarely after modern lensectorny/vitrectomy. The authors performed directed glaucoma evaluations of 34 eyes of 26 children. Based on intraocular pressures of 26 mmHg or greater, glaucoma was diagnosed in 8 (24%) eyes of 7 (27%) children. Glaucoma was found more commonly among children followed more than 60 months and was diagnosed up to 105 months after surgery. Typically, the glaucoma was open angle and asymptomatic. Four children had had previously normal pressures recorded. With longer follow-up, it is likely that more children will be diagnosed with glaucoma after lensectomy / vitrectomy procedures. The authors believe such patients should be followed as glaucoma suspects for the rest of their lives. Ophthalmology 1991; 98:670-674

For many years, late glaucoma has been recognized as a common problem after surgery for pediatric cataract.l'" In a review of 15 studies of pediatric aphakia performed between 1943 and 1975, Francois' found an average incidence ofglaucoma of 5.5%, with some authors reporting an incidence of 13 to 16%. Often, glaucoma is not recognized until years after cataract removal. During the late 1970s, microscopically controlled, automated lensectomy/vitrectomy gradually replaced oneand two-staged needling as a method of pediatric cataract extraction.' Lensectomy/vitrectomy remains the most commonly used technique today." It was hoped that by removing lens and capsular remnants more effectively, such surgery would minimize postoperative inflammation and pupillary block and would decrease the incidence of glaucoma. 3,5-7

In fact, initial reports have been encouraging. Parks" found no cases of chronic glaucoma among 99 eyes operated on with the Ocutome. Whereas Chrousos and associates' found a 6.1% incidence ofglaucoma after various other surgical techniques, no cases were apparent among 54 eyes operated on with the Ocutome. In a longer follow-up study that was undertaken recently, Keech and associates" found an 11% incidence of glaucoma after lensectomy/vitrectomy, During the past 2 years, we encountered several children with late glaucoma after lensectomy/vitrectomy, Because most had no specific symptoms to suggest glaucoma, we were prompted to call in other pediatric patients with aphakia for a directed glaucoma evaluation.

PATIENTS AND METHODS Originally received: November 5, 1990. Revision accepted: January 9, 1991. 1

2

Department of Ophthalmology, Albany Medical College, Albany. Department of Biometry and Statistics, State University of New York, Albany.

Supported in part by training grant EY0703702 and research grant EY05816 from the National Institutes of Health, National Eye Institute, Bethesda, Maryland, to the Albany Medical College Department of Ophthalmology, and by an unrestricted grant from Research to Prevent Blindness, Inc, New York, New York. Reprint requests to John W. Simon, MD, Albany Medical College, Department of Ophthalmology, Albany, NY 12208.

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The families of 42 consecutive children who underwent cataract surgery (before the age of 11 years) at the Albany Medical Center between 1981 and 1987 were contacted by mail. A letter was sent in which we expressed our concern that these children might be at risk ofglaucoma and suggested that these children return for examination. The 26 patients (34 eyes) that we studied ranged in age from 1 week to 127 months (x = 26 months) at the time of surgery and from 17 to 134 months (x = 83.6 months) at the time of glaucoma evaluation. In patients with aphakic glaucoma that was previously documented, the time of

SIMON et al •

PEDIATRIC GLAUCOMA

Table 1. Eyes with Glaucoma Patient No.

Age (mos) at SX

Age (mas) at OX

lOP (mmHg)

1 2 3 4 5 (00) 5 (OS) 6 7

58 1 12 2.5 3.5 3.5 5 1.8

127 80 82 72 101 109 82 17

26 40 30 44 32 27 50 27

lOP of Fellow Eye (mmHg)

10 23 10 27* 32' 15 14

CD

CR

CR/T

0.4 0.8 0.6 0.15 0.4 0.5 0.8 0.7

- 0.35t +10.25 +2.5 +8.0 +13.25 +14.0 +10.0 +20.0

-0.05 -0.07 +0.02 -0.10 -0.08 -0.04 -0.12 -0.13

SX = tensectomv/vitrectomy surgery; OX = glaucoma diagnosis; lOP = intraocular pressure; CD = cup-to-disc ratio; CR (in spherical equivalent); CR/T = change in cycloplegic refraction (see text); 00 = right eye; OS = left eye. * Bilateral glaucoma in bilateral aphakia. t Following epikeratophakia.

= cycloplegic refraction

etry and IS patients (18 eyes) could not cooperate for gonioscopy. One child was evaluated under anesthesia. In cooperative patients, computerized image analysis of the optic nerve head (Topcon Imagenet System, Paramus, NJ) and automated visual fields (Humphrey, Octopus) were performed.

RESULTS

Fig 1. Optic nerve analysis from the left eye of patient 5 shows glaucomatous cupping.

glaucoma evaluation was taken as the time glaucoma was first diagnosed. All patients were evaluated by us (JWS and STS), following a standard protocol. Demographic data were tabulated from a chart review and included characterizations of both cataract types and surgical procedures, including operative and postoperative complications. All procedures were limbal lensectomy/vitrectornies, performed by JWS or RAe with the Ocutome, which followed closely the method described by Parks. 6 Previously recorded intraocular pressures were tabulated. Routine examination included cycloplegic refraction , which was compared with the last similar measurement performed at least I year earlier, and best corrected visual acuity, Glaucoma evaluation included assessment of corneal diameter, slit-lamp examination, applanation tonometry, and estimation of glaucomatous optic nerve damage (if any). Two patients (3 eyes) were unable to cooperate for applanation tonom-

Based on intraocular pressures of 26 mmHg or greater, glaucoma was diagnosed in 8 (24%) eyes of7 (27%) children . We selected this relatively conservative threshold to include in the glaucoma group only those patients whose pressures were clearly elevated. Visual field and optic disc analysis in this age group was difficult. As shown in Table I, pressures ranged from 26 to 50 mmHg (x = 34 mmHg) in patients with glaucoma. Of the eyes with glaucoma, four had elevated pressure at the first successful measurement. However, four had had previously documented normal pressures before the pressure elevations became apparent. In several cases, these normal pressures were documented on numerous occasions. No bilaterally aphakic patient had unilateral glaucoma, although asymmetric pressures were noted in this subgroup occasionally. No unilaterally aphakic patient had bilateral glaucoma. Patient 6 presented with asymmetric cataracts and underwent surgery on only one eye. A pressure of 50 mmHg was noted in the operated eye 67 months postoperatively. The felloweye, with its partial cataract, has had normal pressures consistently. Using logistic regression, glaucomatous optic nerve damage was associated typically with elevated pressures (P = 0.01).8 The cup-to-disc ratio in glaucomatous eyes averaged 0.54 (range, 0.15 to 0.80). In eyes without glaucoma, this ratio averaged 0.19 (range, a to 0.50). Most patients were too young to undergo optic disc photograph y or visual field testing. The optic nerve analysis and computerized visual field of patient 5 are shown in Figures I and 2. 671

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Cataract types are summarized in Table 2. Surgical complications included vitreous at the wound (four eyes), secondary membranes requiring removal (two eyes), and transient vitreous hemorrhage (one eye). Two eyes had retinal detachments, one associated with trauma and the other associated with persistent hyperplastic primary vitreous. Peripheral iridectomies were performed in only two eyes. Slit-lamp examination showed lens remnants in four eyes. Heterochromia was noted in two patients, ectropion uveae in one eye, microphthalmos in two eyes, and increased corneal diameter in one eye (patient 8). One eye that did have glaucoma (patient 1) had undergone epikeratophakia. All other eyes were corrected with contact lenses or with spectacles. With the exception of patient 1, eyes with glaucoma ranged in spherical equivalent from +2.5 diopters (D) to +20.0 D (x = + 11.14 D). Eyes without glaucoma ranged from +6.0 D to +21.0 D (x = + 13.78 D). The two means were not statistically different (P = 0.26). The rate of change in refraction for eyes with glaucoma ranged from -0.12 Dzyear to +0.02 Dzyear (x = -0.07 Dyyear). For eyes without glaucoma, refraction changed from -0.23 Dryear to +0.09 Dzyear (x = -0.05 Dzyear). Best corrected visual acuities ranged from 20/30 to hand motions (x = 20/510) for eyes with glaucoma and 20/30 to hand motions (x = 20/510) for eyes without glaucoma. Except for a few peripheral anterior synechiae, gonioscopy showed open angles in 15 of 16 eyes. One child (patient 8) had unsuspected angle closure with broad peripheral anterior synechiae 15 months postoperatively. Her corneal diameter was 12.75 mm (compared with 12.0 mm in the fellow eye), and she had mild photophobia. No other child had photophobia or corneal enlargement, and none had breaks in Descemet's membrane. One asymptomatic child (patient 4) had mild microcystic corneal edema. The relationship between the diagnosis of glaucoma and other variables that may be prognostic was investigated using logistic regression.f No association could be found between glaucoma and age at surgery, cataract type, microphthalmos, abnormal slit-lamp appearance, surgical complication, visual acuity, refractive error, or refractive change. With the exception of the one eye with angle closure, glaucoma first became apparent 69 to 105 months (x = 82 months) after surgery. Of 14 eyes followed less than 60 months since lensectomy, this was the only one (7%) with glaucoma. Of 17 eyes followed longer than 60 months, 7 (41 %) had glaucoma. This difference is significant by chisquare analysis (P = 0.03). Figure 3 shows a "survival function," depicting the incidence of glaucoma diagnosis by time since surgery.

DISCUSSION Reports of pediatric lensectomy/vitrectomy suggest an improved prognosis when compared with previous sur-

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Fig 2. Automated visual field from the left eye of patient 5 shows nonspecific changes and poor reliability indices.

Table 2. Cataract Type Type of Cataract

No. of Eyes

Nuclear or diffuse Posterior subcapsular PHPV Lamellar Posterior lenticonus APC Traumatic

12 7 5 4

2 2 2

PHPV = persistent hyperplastic posterior vitreous; APC = progressive anterior polar cataract.

GLAUCOMA SURVIVAL CURVE

ec

POST-OPERATNE INTERVAL (moe.)

Fig 3. Survival curve showing proportion of patients free of glaucoma as a function of time since surgery. Notice the "guarantee time" ends abruptly between 60 and 80 months.

SIMON et al •

PEDIATRIC GLAUCOMA

gical techniques, and glaucoma has been a particularly infrequent complication.V" ? Because the procedure was introduced only recently, these reports have been based on relatively short periods of follow-up. Chrousos and associates,' for example, found glaucoma in 24 (6.1 %) eyes after a variety of surgical techniques. Eighteen cases became apparent after a 3-year follow-up period, and 12 became apparent after a 6-year follow-up period. Their finding of no glaucoma after lensectomy/ vitrectomy was based on an average 2-year follow-up period. More dated literature includes reports of glaucoma presenting for the first time as long as 45 years after surgery for pediatric

cataract.'

Our data, and that of Keech and associates," indicate that glaucoma may continue to threaten aphakic children, even those undergoing lensectomy/vitrectomy, many years after surgery. In fact, the survival curve depicted in Figure 2 suggests that there is a "guarantee time" of approximately 5112 years before glaucoma becomes apparent. Perhaps the most troubling aspect of our data is that, had this study been undertaken 2 or 3 years ago, we would have agreed with previous authors that glaucoma is exceptional in these patients. Of the 17 eyes that were followed for at least 5 years after surgery, 7 (41%) had glaucoma. The relatively high incidence of glaucoma in our patients may reflect, in addition to their longer period of follow-up, the directed glaucoma examination they received. All but 2 of the 26 children underwent applanation tonometry successfully. More of our patients may be diagnosed with glaucoma in the future. Glaucoma evaluation in young children can be difficult. Without cooperation, applanation pressures may be inaccurate, if they can be measured at all. The need to remove a contact lens for tonometry is an added obstacle. Therefore, some children may have had elevated pressures for months or years before they were first measured successfully. Careful examination of the optic nerve is often impeded by nystagmus, small pupillary openings, and poor cooperation. Optic nerve analysis may be helpful in selected cases (Fig I). Perimetry testing is difficult for many children, especially those with poor fixation (Fig 2). Computerized interpretation is complicated typically by unreliability and by co-existing amblyopia. For all the se reasons, part of the "guarantee time" ma y simply reflect a delay in diagnosis . However, several patients had had normal pressures documented, in some cases on as many as six previous occasions, before pressure elevations were first documented. Prior reports emphasize the importance of angle abnormalities as a key to understanding the development of glaucoma, especially following older surgical techniques. Walton 7 believes pupillary block and chronic angle closure from peripheral anterior synechiae are common. Phelps and Arafar' found subtle angle abnormalities in patients with open-angle glaucoma. Keech and associates" noted changes similar to those of congenital glaucoma, including a flat iris plane with poorly defined scleral spur and ciliary body.

With the exception of one child who had pupillary block , our patients have all had normal, open angles. Some of the children were uncooperative for gonioscopy, and subtle angle abnormalities may have escaped detection. However, none had angle anomalies we could associate with congenital or developmental glaucoma. None of our patients had rubella or Lowe's syndrome, and only the one patient with pupillary block had corneal enlargement. In the other patients, the few peripheral anterior synechiae were limited to a small area immediately adjacent to the surgical entry site. The pathogenesis of the glaucoma remains undetermined. Phelps and Arafar' suggested it may be, along with the cataracts, a manifestation of a single ocular syndrome. Certainly, the anterior segments of these eyes are fundamentally abnormal. It is conceivable that the developmental defect responsible for producing the cataracts somehow also affected outflow, causing open-angle glaucoma. Our experience with patient 6 refutes this suggestion. This child, with asymmetric cataracts, underwent lensectomy/vitrectomy on only one eye. He developed glaucoma in the operated eye but not in the unoperated eye with its partial cataract. Alternatively, the glaucoma could have been caused in some way by the surgery. The absence of slit-lamp and gonioscopic changes, the delay in presentation, and the relatively complete removal of lens material made possible by lensectomy/vitrectorny all make surgical damage or postoperative inflammation appear unlikely. The prognosis in patients with glaucoma also remains uncertain, as the period of follow-up has been brief. To date, all but two eyes have been controlled medically (below 21 mmHg) with a combination of miotics and betablockers. Two children (patients 6 and 7) have required Molteno implants. Pressures in these children remain below 25 mmHg. We have considered several alterations in our management of pediatric cataract patients. Although pupillary block after this surgery is rare , we have begun adding a peripheral iridectomy as a precaution. Attempting to measure pressure postoperatively in young children is worthwhile, but we continue to experience difficulties despite redoubled efforts. Pressure recordings under anesthesia may be falsely low but may be warranted in uncooperative patients." The risk of glaucoma seems higher 5 years or more after surgery. Unfortunately, myopic shifts in refraction, recently reported by Egbert and Kushner," were not consistently apparent in the patients with g1aucoma.' Certainly, this finding is useful in individual patients, however, and may indicate additional investigation. We recognize the potential for bias in this retrospective study. It is possible that, had we been able to examine all of the children who underwent lensectomy/vitrectomy, the incidence of glaucoma would have been different. Based on our experience, however, we believe that patients who undergo this surgery should be followed as glaucoma suspects for the rest of their lives. Further study of patients with pediatric aphakic glaucoma may suggest other alter-

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ations in surgical technique and postoperative follow-up in the future.

REFERENCES 1. Francois J. Late results of congenital cataract surgery. Ophthalmology 1979; 86:1586-98. 2. Phelps CD, Arafat Nt. Open-angle glaucoma following surgery for congenital cataracts. Arch OphthalmoI1977; 95:1985-7. 3. Chrousos GA, Parks MM, O'Neill JF. Incidence of chronic glaucoma , retinal detachment and secondary membrane surgery in pediatric aphakic patients . Ophthalmology 1984; 91:1238-41 .

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4. Keech RV, Tongue AC, Scott WE. Compl ications after surgery for congenital and infantile cataracts. Am J OphthalmoI1989; 108:13641. 5. Pressman SH, Crouch ER Jr. Pediatric aphakic glaucoma. Ann OphthalmoI1983; 15:568-73. 6. Parks MM. Visual results in aphakic children . Am J Ophthalmol1982; 94:441-9. 7. Walton OS. Glaucoma secondary to operation for childhood cataract. In: Epstein DC, ed. Chandler and Grant's Glaucoma . Philadelphia: Lea & Febiger, 1986; 521-5. 8. Bishop YMM, Feinberg SE, Holland PW. Discrete MultivariateAnalysis: Theory and Practice. Cambridge , MA: MIT Press, 1975. 9. Egbert JE, Kushner BJ. Excessive loss of hyperopia : a presenting sign of juvenile aphakic glaucoma . Arch Ophthalmol 1990; 108: 1257-9.