Outcomes of Ahmed Glaucoma Valve Implantation in Children with Primary Congenital Glaucoma

CLINICAL SCIENCES Outcomes of Ahmed Glaucoma Valve Implantation in Children With Primary Congenital Glaucoma

Yvonne Ou, MD; Fei Yu, PhD; Simon K. Law, MD, PharmD; Anne L. Coleman, MD, PhD; Joseph Caprioli, MD

Objectives: To evaluate the long-term efficacy of in- children had a mean (SD) age of 1.8 (2.6) years, a mean traocular pressure reduction and complications of Ahmed (SD) preoperative intraocular pressure of 28.4 (6.7) glaucoma valve (AGV) implantation in children with pri- mm Hg, and a mean (SD) follow-up time of 57.6 (48.0) mary congenital glaucoma. months. The cumulative probability of success was 63% in 1 year and 33% in 5 years. After a second AGV im- Methods: The medical records of patients with pri- plantation, the cumulative probability of success was 86% mary congenital glaucoma who underwent AGV implan- in 1 and 2 years and 69% in 5 years. Hispanic ethnicity tation with a minimum follow-up of 6 months were re- (P=.02) and being female (P=.005) were associated with viewed. The primary outcome measure was cumulative increased risk of failure. probability of success, defined as intraocular pressure greater than 5 mm Hg and less than 23 mm Hg and at Conclusions: Thirty-three percent of AGV implanta- least a 15% reduction from the preoperative intraocular tions in children with primary congenital glaucoma were pressure, without serious complications, additional glau- successful after 5 years of follow-up. With the implan- coma surgery, or loss of light perception. tation of a second AGV, the 5-year success rate increased to 69%. Results: Thirty eyes of 19 children with primary congenital glaucoma who underwent AGV implantation with a minimum follow-up of 6 months were reviewed. The Arch Ophthalmol. 2009;127(11):1436-1441

RIMARY CONGENITAL GLAU- The Ahmed glaucoma valve (AGV) coma (PCG) is present at (New World Medical, Inc, Rancho birth but often goes unrec- Cucamonga, California) is a tube shunt ognized until increased in- device with a unidirectional flow-restric- traocular pressure (IOP) tive mechanism designed to prevent post- damagesP ocular structures and produces operative hypotony. The success rates revision loss. Primary congenital glaucoma ported for this device in the pediatric is a potentially blinding disease that usu- population range from 58% to 93% in ally does not respond adequately to medi- achieving IOP of less than 21 mm Hg, but cal treatment. Although goniotomy and these rates have been in mixed popula- trabeculotomy are associated with good tions of children with a variety of pediat- early success rates, eventually 20% of these ric glaucoma diagnoses and with short- procedures fail and many children with term follow-up.8,9,19,20 These reports include PCG require additional surgery to con- children with congenital glaucoma as well trol IOP in the long-term.1-3 Various sur- as children with secondary diagnoses in- gical approaches have been proposed, including aphakia or pseudophakia, Sturge- cluding trabeculectomy with or without Weber syndrome, uveitic glaucoma, an- adjunctive antimetabolites,4,5 nonpenetrat- iridia, and anterior segment dysgenesis. ing external trabeculectomy,6 combined Because of the heterogeneity in the mecha- trabeculotomy and trabeculectomy,7 glau- nisms of glaucoma secondary to these vari- coma drainage devices,8-11 and cyclode- ous disorders, we evaluated the long-term structive procedures.12,13 Trabeculec- surgical efficacy of AGV implantation in tomy with mitomycin C has shown children with PCG. promise, with studies reporting 52% to 95% success rates.14-16 However, the in- METHODS Author Affiliations: Glaucoma creased success with the addition of anti- Division, Jules Stein Eye metabolites has also resulted in well- Institute, David Geffen School recognized long-term complications such This was a retrospective study of patients of Medicine, University of as bleb failure, bleb leak, and bleb- with PCG who underwent AGV implantation California, Los Angeles. related endophthalmitis.16-18 from January 1, 1995, to December 31, 2007,

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©2009 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/25/2021 at the Glaucoma Division, Jules Stein Eye Institute, University The eye was the unit of analysis. However, repeat analysis of California, Los Angeles, with a minimum of 6 months of was performed with 1 eye per patient (n=19 patients), using follow-up. Children with secondary diagnoses including the first eye that underwent AGV implantation. In cases where aphakia or pseudophakia, Sturge-Weber syndrome, uveitic both eyes received AGV implantation simultaneously, the right glaucoma, aniridia, and anterior segment dysgenesis were eye was evaluated. excluded. This study was approved by the University of Cali- Kaplan-Meier survival analyses were used to assess the long- fornia, Los Angeles institutional review board. term success rates according to the criteria defined earlier. In addition, Cox proportional hazards regression analysis was used DATA COLLECTION to determine the predictive factors for failure. The following potential predictors were evaluated in a univariate analysis: age, Preoperative data were collected from the records of the pa- sex, ethnicity, baseline IOP, preoperative cup-disc ratio, pres- tients and included age at the time of surgery, sex, race, eye ence of preoperative corneal edema, preoperative medications laterality, mean IOP prior to AGV implantation, prior ocular used, and number of previous glaucoma surgical procedures. surgical procedures, specific glaucoma diagnosis and other ocu- In comparing Hispanic vs non-Hispanic patients, continuous lar history, number of medications used, and type of AGV used variables were compared using the Kruskal-Wallis test, whereas in the surgery. categorical variables were compared using the Fisher exact test. Postoperative data were collected from the records of the The Cochran-Armitage test was used to evaluate the underly- ing trend in postoperative medication use and changes in cup- patients from all consecutive visits. Collected data include IOP Ͻ measurements, number of medications used, axial length, cup- disc ratios. P .05 was considered statistically significant. All disc ratio, presence of corneal edema and Haab striae, surgical statistical analyses were performed using SAS version 9.1 sta- complications, additional surgical procedures performed, and tistical software (SAS Institute, Inc, Cary, North Carolina). follow-up time. Cup-disc ratios were recorded during the evaluation under anesthesia or at the time of surgical intervention RESULTS by 1 of the 3 surgeons (J.C., A.L.C., and S.K.L.). Quantitative visual acuity information was limited due to patient age at the time of surgery but was obtained at postoperative visits when- PREOPERATIVE CHARACTERISTICS ever possible. Thirty eyes of 19 patients were included in the study. SURGICAL TECHNIQUE Twelve patients (63%) were male. Eight patients (42%) were white, 8 patients (42%) were Hispanic, and 3 pa- The polypropylene and silicone single-plate AGVs (models S-2 tients (16%) were Asian. The mean (SD) age at the time and FP-7, respectively) were implanted by 3 experienced sur- of AGV implantation for each eye was 1.8 (2.6) years, geons (J.C., A.L.C., and S.K.L.) using similar techniques. A for- with a range of 0.02 to 9.9 years. Twenty-eight eyes (93%) nix-based flap of the conjunctiva and Tenon capsule was cre- underwent prior glaucoma surgery, with 7 (23%) un- ated in the superior temporal or superior nasal quadrant, with dergoing a single angle surgical procedure (goniotomy the anterior edge of the plate secured with nondissolvable su- or trabeculotomy) and 18 (60%) undergoing 2 or more ture 10 mm posterior to the superior temporal corneolimbal junction or 8 mm posterior to the superior nasal corneolimbal angle surgical procedures. Among the 7 patients who had junction. The tube was flushed with balanced salt solution to only a single procedure prior to AGV implantation, 2 were ensure patency before insertion through a scleral track that was of older age (mean age, 8.4 years) at the time of implan- created with a 22- or 23-gauge needle into the anterior cham- tation, suggesting that the single angle surgical proce- ber. Viscoelastic was injected to reform the anterior chamber dure controlled the IOP for a relatively long time before as needed at the discretion of the individual surgeon. A com- further intervention was necessary. The remaining 5 pa- mercially available processed pericardial graft (Tutoplast; IOP, tients had IOP uncontrolled after a single angle surgical Inc, Costa Mesa, California) was used to cover the scleral en- procedure, and a decision was made to proceed to AGV try site and the anterior 8 mm of the tube by securing it to the implantation. Three eyes (10%) also underwent trabecu- episcleral surface with interrupted 8-0 polyglactin sutures (Vic- lectomy in addition to angle surgery prior to drainage de- ryl; Ethicon, Inc, Somerville, New Jersey). The conjunctiva and Tenon capsule were then reapproximated to the limbus with vice implantation. The mean (SD) number of prior glau- 9-0 polyglactin sutures. coma surgical procedures was 1.8 (0.9). The mean (SD) preoperative IOP was 28.4 (6.7) mm Hg, while the mean (SD) IOP at the last follow-up was 17.7 (6.7) mm Hg. STATISTICAL METHODS Data on glaucoma medications used prior to AGV im- The primary outcome measure was surgical success, defined as plantation were not available for 3 eyes. Nine eyes (33%) IOP less than 23 mm Hg and greater than 5 mm Hg and at least did not receive any glaucoma medications prior to AGV a 15% reduction of IOP from baseline. Failure was established implantation, 13 eyes (48%) received 1 glaucoma medi- when the IOP was outside the success range on 2 consecutive vis- cation prior to AGV implantation, and 5 eyes (19%) re- its at least 6 months after AGV implantation or in the case of se- ceived 2 glaucoma medications prior to AGV implanta- rious complications, loss of light perception, or need for addition, with a mean (SD) number of glaucoma medications tional glaucoma surgery (excepting tube repositioning, trimming, of 0.9 (0.7). Table 1 summarizes the baseline charac- or scleral patch graft reinforcement for tube exposure). Serious teristics of the study population. complications included retinal detachment, endophthalmitis, su- prachoroidal hemorrhage, aqueous misdirection and pupillary block, and phthisis. Secondary outcome measures were IOP level, IOP CONTROL number of medications used, and cup-disc ratio at 3, 6, 12, 24, 36, 48, and 60 months after surgery. Intraoperative and postop- The mean (SD) follow-up time was 57.6 (48.0) months, erative complications were also recorded. with a range of 8 to 166 months. The mean (SD) IOP de-

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©2009 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/25/2021 Table 1. Preoperative Demographics and Length 1.0 of Follow-up in Patients With Primary Congenital Glaucoma Who Underwent Ahmed Glaucoma Valve Implantation 0.8

Characteristic Value 0.6 Patients, No. 19 Sex, No. (%) 0 Medications 1-3 Medications Male 12 (63) 0.4 Female 7 (37) Proportion of Eyes Ethnicity, No. (%) 0.2 White 8 (42) Asian 3 (16) Hispanic 8 (42) 0 Eyes, No. 30 0 12 24 36 48 60 Age at implantation, y Follow-up, mo Mean (SD) 1.8 (2.6) Range 0.02-9.9 Median 1.0 Figure 2. The proportion of eyes requiring no medications vs 1 to 3 medications during follow-up in patients with primary congenital glaucoma Preoperative IOP, mm Hg who underwent Ahmed glaucoma valve implantation. Mean (SD) 28.4 (6.7) Range 14.0-40.0 Preoperative medications used, No. (n=27) Mean (SD) 0.85 (0.72) 1.0 Range 0-2 Prior glaucoma surgical procedures, No. Mean (SD) 1.8 (0.9) 0.8 Range 0-4 Duration of follow-up, mo 0.6 Mean (SD) 57.6 (48.0) Improvement Range 8-166 or no change 0.4 Worsening

Abbreviation: IOP, intraocular pressure. Proportion of Eyes 0.2

40.0 0 0 12 24 36 48 60 35.0 Follow-up, mo 30.0

25.0 Figure 3. The proportion of eyes with improvement or no change vs worsening in cup-disc ratio during follow-up in patients with primary 20.0 congenital glaucoma who underwent Ahmed glaucoma valve implantation.

IOP, mm Hg IOP, 15.0 cent of eyes did not require medications at 3 months, 10.0 whereas 11% of eyes did not require medications at 5 years. 5.0 This trend was found to be statistically significant using 0.0 the Cochran-Armitage trend test (P=.002). Figure 2 dis- Preoperative 3 6 12 24 36 48 60 n = 22 n = 25 n = 24 n = 19 n = 12 n = 9 n = 9 plays the proportion of eyes requiring no medications vs Time, mo 1 to 3 medications during the follow-up period.

Figure 1. Course of mean intraocular pressure (IOP) before surgery CUP-DISC RATIO (preoperative) and during follow-up in patients with primary congenital glaucoma who underwent Ahmed glaucoma valve implantation. Error bars The proportion of eyes that demonstrated no change or im- indicate 1 SD. provement in cup-disc ratio on follow-up examinations as compared with baseline increased over time. The Cochran- creased from a preoperative value of 28.4 (6.7) mm Hg Armitage trend test demonstrated that the trend of wors- to 16.6 (4.3) mm Hg at 12 months and 17.7 (6.7) mm Hg ening in cup-disc ratio over time was not statistically sig- at 60 months after AGV implantation. All intervening nificant (P=.15). Figure 3 displays the proportion of eyes mean postoperative IOP measurements were decreased demonstrating no change or improvement vs worsening from baseline (PϽ.001). Figure 1 displays the course in cup-disc ratio over the follow-up period. of the mean IOP during the study. SURGICAL COMPLICATIONS NUMBER OF MEDICATIONS AND ADDITIONAL SURGICAL PROCEDURES

The proportion of eyes requiring IOP-lowering medica- While there were no intraoperative complications of AGV tions increased over 5 years of follow-up. Sixty-three per- implantation, postoperative complications were as fol-

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©2009 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/25/2021 1.0 Table 2. Risk Factors for Surgical Failure in Patients With Primary Congenital Glaucoma Who Underwent Single Ahmed Glaucoma Valve Implantation and Results 0.8 From Univariate Cox Proportional Hazards Regression Models 0.6 P Risk Factor RR (95% CI) Value 0.4 Age 1.02 (0.86-1.21) .85 Male vs female 0.18 (0.06-0.60) .005 0.2

Proportion of Eyes Successful Hispanic vs non-Hispanic 3.67 (1.25-10.83) .02 Preoperative IOP, per mm Hg 0.97 (0.91-1.05) .48 0 Preoperative cup-disc ratio 1.13 (0.80-1.59) .50

0 24 48 72 96 120 144 168 Presence of preoperative corneal edema 0.94 (0.35-2.55) .91 Ն Follow-up, mo Preoperative medications, 1 vs 0 0.47 (0.16-1.37) .16 Prior glaucoma surgical procedures, 1.10 (0.35-3.47) .88 Ն2vsՅ1 Figure 4. Kaplan-Meier cumulative probability curve of success (solid line) and 95% confidence interval (dashed lines) in patients with primary Abbreviations: CI, confidence interval; IOP, intraocular pressure; congenital glaucoma who underwent Ahmed glaucoma valve implantation. RR, relative risk.

lows. Four eyes (13%) required tube trimming because of tube-cornea touch, while 2 eyes (7%) required repeat 1.0 scleral patch graft reinforcement because of tube exposure. Transient hypotony, defined as IOP equal to or less 0.8 than 5 mm Hg, occurred in 2 eyes (7%). Shallow anterior chamber necessitating reformation of the chamber 0.6 occurred in 1 eye (3%). Three eyes (10%) underwent pen-

etrating keratoplasty and 4 eyes (13%) underwent sub- 0.4 sequent cataract extraction. Three eyes (10%) underwent cycloablative procedures, 2 of which were eyes that 0.2 subsequently failed due to IOP criteria. Postoperative en- Proportion of Eyes Successful dophthalmitis after tube revision occurred in 1 eye (after the eye had already failed). One eye was enucleated 0 after endophthalmitis developed subsequent to cataract 0 12 24 36 48 60 extraction performed by a surgeon from the pediatric oph- Follow-up, mo thalmology service. Figure 5. Kaplan-Meier cumulative probability curve of success (solid line) and 95% confidence interval (dashed lines) in patients with primary SURGICAL SUCCESS AND RISK FACTORS congenital glaucoma who underwent a second Ahmed glaucoma valve FOR FAILURE implantation.

In Kaplan-Meier survival analysis, there was a 63% success rate at 1 year, a 50% success rate from years 2 to 3, neal edema, preoperative medication use, and number a 41% success rate at year 4, and a 33% success rate at 5 of prior glaucoma surgical procedures were not associ- years (Figure 4). Six eyes (20%) failed according to IOP ated with increased risk of failure (Table 2). We re- criteria, with 5 eyes failing due to IOP greater than 23 peated the analysis using only the first eye of each pa- mm Hg and 1 eye failing due to IOP less than 5 mm Hg. tient to receive an AGV, and both Hispanic ethnicity An additional 10 eyes (33%) failed because a second AGV (P=.02) and being female (P=.04) remained statisti- was implanted, although 8 of these eyes did not fail sec- cally significant risk factors for failure. ondary to IOP criteria. There were no failures due to se- Given that 10 eyes (33%) from 6 patients required a vere complication or loss of light perception, although second tube, survival analysis was performed using the 1 eye did have endophthalmitis after tube revision that same failure criteria to examine the success of the sec- resulted in a phthisical eye. However, this eye had al- ond AGV implantation in these eyes. In Kaplan-Meier sur- ready failed secondary to IOP criteria prior to the tube vival analysis, the success rate was 86% at 1 and 2 years revision surgery. When this analysis was repeated using and 69% at 5 years (Figure 5). Two eyes failed because only the first eye of each patient to receive an AGV (19 a third AGV was implanted at 27 months and 69 months eyes), similar success rates were found: 68% at 1 year and after the second AGV implantation, although they did not 31% at 5 years (data not shown). fail due to IOP criteria. The third eye failed due to IOP In the Cox proportional hazards model, Hispanic eth- greater than 23 mm Hg on 2 consecutive visits 12 months nicity was associated with a 3-fold increased risk of fail- after the second AGV implantation, and a third AGV was ure (P=.02) in univariate analysis. Being male had a de- implanted 14 months after the second AGV implanta- creased risk of failure (P=.005). Age, preoperative IOP, tion. Because of the small number of eyes, no risk factor preoperative cup-disc ratio, presence of preoperative cor- analysis was performed.

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©2009 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/25/2021 In this study, 3 eyes (10%) required a third AGV im- risk factor for time to failure. However, the criteria for plantation, with 2 eyes (66%) maintaining adequate IOP failure included tube malposition, which was defined as control at the last follow-up (11 months and 48 months). any change in the optimal position of the tube or valve One eye (33%) failed due to IOP greater than 23 mm Hg plate that resulted in uncontrolled IOP or other compli- on 2 consecutive visits 6 months after the last AGV im- cations (tube retraction, tube-endothelium contact, tube- plantation. iris contact, valve plate extrusion). In their study, of the 11 eyes that were considered failures, 9 were eyes with congenital glaucoma, with 56% failure secondary to tube COMMENT malposition. However, in comparison with our study, the follow-up time was shorter at 12 and 24 months. In con- In PCG, the cumulative probability of success with a single trast, other studies have not found any correlation be- AGV implant was 63% at 1 year of follow-up but de- tween surgical failure and glaucoma type in the pediat- creased to 33% at 5 years of follow-up. However, with a ric population.8,9,20,21 One of the largest studies, published second AGV implantation, the success was 86% at years by O’Malley Schotthoefer and associates, examined the 1 and 2 of follow-up and 69% at 5 years. Hispanic eth- long-term outcome of aqueous drainage devices in 38 eyes nicity increased the risk of failure of AGV implantation with congenital glaucoma and 32 eyes with aphakic glau- by 3-fold in our study. coma. One-year success rates were 92% and 90% in the The safety and efficacy of aqueous shunt devices in congenital and aphakic groups, respectively, but these pediatric glaucoma have been established in prior stud- decreased to 42% and 55% after 10 years. In the congen- ies.8-11,19,20 However, PCG is a disease distinct from pe- ital glaucoma group, AGVs were implanted in 27 of the diatric glaucomas, which is a term that may include PCG 38 eyes (71%) and Baerveldt implants were placed in the but also includes secondary glaucomas such as aphakic remainder. In addition, 10 of the 38 eyes (26%) had other glaucoma or glaucomas associated with increased epi- nonglaucoma surgical procedures prior to aqueous drain- scleral venous pressure. Currently, there is no consen- age device placement, including cataract surgery, pen- sus as to the preferred surgical algorithm after failure of etrating keratoplasty, and vitrectomy. Thus, there were angle surgery and there may be wide variation in recom- significant differences between the patients with con- mended treatment by centers experienced in the treat- genital glaucoma examined in the study by O’Malley ment of PCG. Owing to the rarity of the disease, ran- Schotthoefer and associates compared with our study, domized prospective trials have not been performed. We which included patients with PCG who had only glau- are unaware of other studies evaluating the long-term out- coma surgical procedures previously and had only AGVs comes of AGV implantation performed for PCG or stud- implanted. ies that report the long-term outcomes of a second AGV Tube-related problems were the most common com- implantation. plication after AGV implantation in this study, most of Although aqueous shunt devices have demonstrated which were due to tube-corneal apposition, which ne- considerable success in pediatric glaucoma, it is diffi- cessitated tube trimming in 4 eyes (13%). Additionally, cult to compare surgical success rates because prior stud- reoperation secondary to tube exposure was required in ies examining surgical outcomes of drainage devices vary 2 eyes (7%). Tube migration is thought to be associated in the populations studied, lengths of follow-up, and types with shrinkage of the sclera and globe after IOP reduc- of devices implanted. The cumulative probability of suc- tion, with the tube repositioning more anteriorly and cess varies widely in different studies, ranging from 42% closer to the corneal endothelium. Additionally, it is pos- at 10 years of follow-up in a retrospective case series by tulated that vigorous eye rubbing can move the tube for- O’Malley Schotthoefer et al21 comparing glaucoma drain- ward toward the cornea. Lastly, as the child’s eye grows, age device surgery in congenital glaucoma and aphakic the initially well-positioned tube may rotate more ante- glaucoma to a 93% success rate of AGV implantation in riorly over time. We recommend that the tube is placed pediatric glaucoma at 12 months in a retrospective case at least 1 mm posterior to the limbus and that the tube series by Morad et al.20 Our short-term (63% at 1 year) is positioned parallel to the iris. Our tube revision rate and long-term (33% at 5 years) survival rates are slightly is similar to other studies that examined glaucoma drain- lower than the rates reported in the literature with simi- age device implantation in pediatric glaucomas.9,20-22 lar success criteria, although the studied populations in- Trabeculectomy with or without antimetabolites is an- cluded children with other types of glaucoma, variabil- other option in the management of PCG, although the ity in phakic status, and variability in type of glaucoma introduction of antifibrotic agents has resulted in higher drainage device implanted. rates of late-onset bleb-related endophthalmitis com- There is controversy as to whether AGV implanta- pared with the rates in adults.16-18 A retrospective, com- tion has a higher rate of failure in patients with PCG com- parative case series published by Beck et al22 comparing pared with patients with other diagnoses.8,9 While to our aqueous shunt devices with trabeculectomy with mito- knowledge no studies have examined the outcomes of mycin C reported a cumulative probability of success of AGV implantation in children with exclusively PCG, 87% in the aqueous shunt group and 36% in the trab- Djodeyre et al19 reported shorter mean survival time with eculectomy group during the first year of follow-up. This AGVs implanted in 17 eyes with congenital glaucoma decreased to 53% and 19% for the aqueous shunt and tra- compared with 18 eyes with other diagnoses (Sturge- beculectomy groups, respectively, at 6 years of follow- Weber syndrome, postoperative glaucoma, etc). Having up. While that study included only children aged 24 more than 2 previous glaucoma interventions was also a months or younger, the study population was heteroge-

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©2009 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/25/2021 neous and consisted of patients with congenital glau- Funding/Support: This work was supported by an un- coma, anterior segment anomalies, varying phakic sta- restricted grant from Research to Prevent Blindness. tuses, and persistent fetal vasculature. In addition, the Previous Presentation: This study was presented at the patients received either the Ahmed or Baerveldt implant. annual meeting of the Association for Research in Vi- Kaplan-Meier survival analysis performed on 2 sub- sion and Ophthalmology; April 28, 2008; Fort Lauder- groups of eyes demonstrated a less favorable surgical out- dale, Florida. come for those eyes in patients of Hispanic ethnicity compared with those of non-Hispanic ethnicity. To our knowledge, this difference has not been reported in prior REFERENCES studies, most likely owing to the rarity of the disease. A review of the literature also did not identify studies dem- 1. Anderson DR. Trabeculotomy compared to goniotomy for glaucoma in children. onstrating worse surgical outcomes for adult Hispanic Ophthalmology. 1983;90(7):805-806. 2. deLuise VP, Anderson DR. Primary infantile glaucoma (congenital glaucoma). patients receiving glaucoma drainage devices. In this Surv Ophthalmol. 1983;28(1):1-19. study, a comparison of various preoperative character- 3. Tanimoto SA, Brandt JD. Options in pediatric glaucoma after angle surgery has istics (ie, age, preoperative IOP, preoperative cup-disc ra- failed. Curr Opin Ophthalmol. 2006;17(2):132-137. tio, preoperative corneal edema, preoperative medica- 4. Fulcher T, Chan J, Lanigan B, Bowell R, O’Keefe M. Long-term follow up of pri- tion use, and previous glaucoma surgery) did not reveal mary trabeculectomy for infantile glaucoma. Br J Ophthalmol. 1996;80(6): 499-502. any differences between Hispanic and non-Hispanic pa- 5. Rodrigues AM, Junior AP, Montezano FT, de Arruda Melo PA, Prata J Jr. Com- tients. Since being female is also associated with in- parison between results of trabeculectomy in primary congenital glaucoma with creased risk of failure in this study, a comparison of pre- and without the use of mitomycin C. J Glaucoma. 2004;13(3):228-232. operative characteristics was performed and did not show 6. Roche O, Beby F, Parsa A, Orssaud C, Dufier JL, Parsa CF. Nonpenetrating external trabeculectomy for congenital glaucoma: a retrospective study. any differences between male and female patients, in- Ophthalmology. 2007;114(11):1994-1999. cluding those of Hispanic ethnicity (data not shown). 7. Mandal AK, Gothwal VK, Bagga H, Nutheti R, Mansoori T. Outcome of surgery To our knowledge, no studies report the long-term out- on infants younger than 1 month with congenital glaucoma. Ophthalmology. 2003; come of a second glaucoma drainage device implanta- 110(10):1909-1915. tion in children with PCG. 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Clinical experience with the eyes that underwent a second AGV implantation in this Molteno implant in advanced infantile glaucoma. J Pediatr Ophthalmol Strabismus. study precluded an analysis of risk factors for subse- 1991;28(2):68-72. quent failure. 12. al Faran MF, Tomey KF, al Mutlaq FA. Cyclocryotherapy in selected cases of congenital glaucoma. Ophthalmic Surg. 1990;21(11):794-798. Our study is limited by its retrospective design be- 13. Phelan MJ, Higginbotham EJ. Contact transscleral Nd:YAG laser cyclophotoco- cause of the differences in preoperative characteristics and agulation for the treatment of refractory pediatric glaucoma. Ophthalmic Surg lack of a prespecified interval of follow-up and data col- Lasers. 1995;26(5):401-403. lection. For example, patients who have undergone prior 14. Mandal AK, Walton DS, John T, Jayagandan A. Mitomycin C-augmented trabeculectomy in refractory congenital glaucoma. Ophthalmology. 1997;104(6): glaucoma surgery or multiple surgical procedures may 996-1001, discussion 1002-1003. have a more severe course of glaucoma and may be more 15. al-Hazmi A, Zwaan J, Awad A, al-Mesfer S, Mullaney PB, Wheeler DT. Effective- susceptible to surgical failure. In addition, because quan- ness and complications of mitomycin C use during pediatric glaucoma surgery. titative visual acuity testing could not be done at the time Ophthalmology. 1998;105(10):1915-1920. of AGV implantation, our ability to comment on visual 16. Beck AD, Wilson WR, Lynch MG, Lynn MJ, Noe R. Trabeculectomy with adjunctive mitomycin C in pediatric glaucoma. Am J Ophthalmol. 1998;126(5):648- outcomes is limited. The study’s strengths are its unifor- 657. mity in PCG population, type of glaucoma drainage de- 17. Waheed S, Ritterband DC, Greenfield DS, Liebmann JM, Sidoti PA, Ritch R. vice used, and its relatively large number of eyes. Bleb-related ocular infection in children after trabeculectomy with mitomycin C. In summary, we report moderate success with IOP con- Ophthalmology. 1997;104(12):2117-2120. 18. Sidoti PA, Belmonte SJ, Liebmann JM, Ritch R. Trabeculectomy with mitomy- trol using the AGV in patients with PCG. However, His- cin-C in the treatment of pediatric glaucomas. Ophthalmology. 2000;107(3): panic ethnicity was a risk factor for surgical failure and 422-429. 20% of eyes required tube revision, either trimming or 19. Djodeyre MR, Peralta Calvo J, Abelairas Gomez J. Clinical evaluation and risk scleral patch graft reinforcement, as the children aged. factors of time to failure of Ahmed Glaucoma Valve implant in pediatric patients. Ophthalmology. 2001;108(3):614-620. 20. Morad Y, Donaldson CE, Kim YM, Abdolell M, Levin AV. The Ahmed drainage Submitted for Publication: December 23, 2008; final re- implant in the treatment of pediatric glaucoma. Am J Ophthalmol. 2003;135 vision received March 12, 2009; accepted March 24, 2009. (6):821-829. Correspondence: Joseph Caprioli, MD, Glaucoma Divi- 21. O’Malley Schotthoefer E, Yanovitch TL, Freedman SF. Aqueous drainage device sion, Jules Stein Eye Institute, David Geffen School of surgery in refractory pediatric glaucomas, I: long-term outcomes. J AAPOS. 2008; 12(1):33-39. Medicine, 100 Stein Plaza, Los Angeles, CA 90095 22. Beck AD, Freedman S, Kammer J, Jin J. Aqueous shunt devices compared with ([email protected]). trabeculectomy with Mitomycin-C for children in the first two years of life. Am J Financial Disclosure: None reported. Ophthalmol. 2003;136(6):994-1000.

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