The use of Ahmed glaucoma valve in the management of pediatric glaucoma Shantha Balekudaru, DNB, Juhie Vadalkar, MS, Ronnie George, MS, and Lingam Vijaya, MS PURPOSE

METHODS

To assess the intraocular pressure control (IOP), changes in visual acuity, complications, reoperation rates and risk factors for failure following Ahmed glaucoma valve implantation in pediatric eyes with glaucoma. The medical records of consecutive patients with glaucoma who underwent Ahmed glaucoma valve implantation from January 2000 to December 2009) were retrospectively reviewed. Only one eye of each patient was included. Subgroup analysis was performed in three groups; group 1 included phakic eyes with primary congenital glaucoma, juvenile open-angle glaucoma, or glaucoma associated with ocular anomalies; group 2 included eyes with glaucoma in aphakia or pseudophakia; group 3 included eyes with other diagnoses. A successful outcome was defined as final IOP between 6 mm Hg and18 mm Hg without loss of light perception or reoperation for glaucoma.

RESULTS

A total of 71 eyes in 71 patients: 15 (21%) in group 1, 47 (66%) in group 2, and 9 (13%) in group 3 were included Successful IOP control was achieved in 44 eyes of 44 patients (62%). Cumulative probabilities of success by Kaplan-Meier analysis at 12 and 24 months was 97% and 80% for the entire group, 100% and 82% for group 1, 95% and 86% for group 2, and 90% and 42% for group 3. Reoperation was necessary for 18 patients (25%), either for tube-related complications or for IOP control. The only significant risk factor for failure was the category of diagnosis (P 5 0.029).

CONCLUSIONS

Ahmed glaucoma valve implantation is an option in the management of pediatric glaucoma; however, reoperations for tube related complications or for persistent elevated IOP is frequently needed. ( J AAPOS 2014;18:351-356)

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raditional surgical approaches to the management of pediatric glaucoma such as goniotomy, trabeculotomy, and combined trabeculotomy and trabeculectomy have high success rates when performed as initial surgical procedures.1-6 However, some of the more refractory secondary pediatric glaucomas, such as those associated with anterior segment dysgenesis, aniridia, Sturge-Weber syndrome, and following congenital cataract surgery, show poor results using these surgical approaches.7-9 Although the use of the adjunctive antifibrotic agent mitomycin C has improved the results of surgery in pediatric glaucoma, the accelerated healing response in the infant eye, the lower scleral rigidity, and the reported increased rates of infection remain a matter for concern.10,11

Author affiliations: Medical Research Foundation and Jadhavbhai Nathamal Singhvi Glaucoma Department, Sankara Nethralaya, Chennai, India Presented as a poster at the 5th World Glaucoma Congress, Vancouver, Canada, July 17-20, 2013. Submitted September 28, 2013. Revision accepted March 12, 2014. Correspondence: Shantha Balekudaru, DNB, Medical Research Foundation, Sankara Nethralaya, 41, College Road, Chennai, India. 600006 (email: shantha.acharya@gmail. com). Copyright Ó 2014 by the American Association for Pediatric Ophthalmology and Strabismus. 1091-8531/$36.00 http://dx.doi.org/10.1016/j.jaapos.2014.03.013

Journal of AAPOS

Glaucoma drainage devices have become popular in the management of pediatric glaucoma. The Molteno, Ahmed, and Baerveldt implants are currently the most popular implants in use in the management of glaucoma in this population. The purpose of this study was to assess the intraocular pressure (IOP) control, changes in visual acuity, complications, reoperation rates and risk factors for failure following implantation of the Ahmed glaucoma valve (AGV; New World Medical Inc, Rancho Cucamonga, CA) in eyes with pediatric glaucoma.

Subjects and Methods The study was approved by the Institutional Review Board and Ethics Committee of the Vision Research Foundation, a subsidiary of the Medical Research Foundation). The medical records of consecutive patients under 18 years of age who underwent implantation of an Ahmed glaucoma valve between January 2000 and December 2009 were retrospectively reviewed. Patients less than 18 years of age with more than 3 months of follow-up were included. If both eyes of a patient underwent implantation surgery, the first eye to have undergone surgery was included. If an eye had undergone surgery with more than one implant, the results of only the first implant were included. Indications for surgery included uncontrolled IOP with medications or progressive optic nerve damage.

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Surgery was performed under general anesthesia in all eyes using either the S-2 model or the FP-7 model. The implant was placed in the superior-temporal quadrant in all eyes at a distance of 8–10 mms from the limbus. The tube was inserted into the anterior chamber, after being primed with Ringer lactate solution, using a 22-, 23-, or 24-gauge needle, at the surgeon’s discretion, parallel to the iris surface, into the ciliary sulcus, or through the pars plana. The use of either an anterior chamber maintainer or vicoelastic solution to keep the anterior chamber formed was left to the surgeon’s discretion. The external surface of the tube was covered with a glycerin-preserved scleral patch graft, secured in place either with 8-0 nylon sutures and with fibrin glue. Postoperative medications consisted of topical steroids, cycloplegics, and topical antibiotics, which were gradually tapered over a period of 6-8 weeks. Aqueous suppressants were introduced in the event of a hypertensive phase. Patients were examined on the first postoperative day, the first week, at 6 weeks, and at various intervals thereafter until the final visit. An examination under anesthesia was performed when patients were uncooperative for evaluation. Complete success was defined as IOP between 6 mm Hg and 18 mm Hg without medications, no loss of light perception, and no loss of vision due to endopthalmitis, choroidal hemorrhage or phthisis during the follow-up period. Qualified success included cases in which the above criteria were fulfilled with the addition of glaucoma medications. Failures were defined as IOP \6 mm Hg or .18 mm Hg, loss of light perception, loss of vision due to endophthalmitis, choroidal hemorrhage, phthisis, removal of the implant or the need for further surgical intervention for IOP control including cyclodestructive procedures. Hypotony, defined as IOP of\6 mm Hg, of more than 2 weeks’ duration was designated as prolonged hypotony; if present at the final visit, hypotony was defined as persistent. The hypertensive phase was defined as IOP of $22 mm Hg noted in the first 3 months following implantation following IOP reduction to \22 mm Hg during the first postoperative week. Eyes with elevated IOP due to either a blocked tube or to tube malposition were excluded from this definition. The following details were extracted from the medical record: age, sex, type of glaucoma, visual acuity measurements when available, details of slit-lamp examination, IOP measurement obtained with Perkins applanation tonometry or with a TonoPen (Mentor; Norwell, MA), gonioscopy, optic disk and fundus evaluation, and pachymetry and axial length measurements when available. Visual acuity was measured using the Snellen chart; measurements were converted to the logarithm of the reciprocal of the minimal angle of resolution (logMAR) for the purpose of statistical analysis. Details of surgeries performed prior to AGV implantation were noted. Operative details included the model of the implant used, the quadrant in which it was placed, the location of the placement of the tube, and intraoperative surgical complications, if any.

Statistical Analysis SPSS for Windows version 12 (SPSS Inc Chicago, IL) was used for the analysis. The Kolmogorov-Smirnov test was applied to

Volume 18 Number 4 / August 2014 test for normal distribution of data. Comparison of continuous data was performed with the independent samples t test for normally distributed data. The Mann-Whitney test and the Wilcoxon signed-rank test were applied to non-normally distributed data. Categorical data were analyzed with the c2 test and the Fisher exact test. A P value of \0.05 was considered to be statistically significant. Subgroup analysis was performed according to the type of glaucoma: group 1 included phakic eyes with primary congenital glaucoma (PCG), juvenile open-angle glaucoma (JOAG), or glaucoma associated with ocular anomalies; group 2 included eyes with glaucoma in aphakia or pseudophakia; group 3 included eyes with other diagnoses. Outcomes were analyzed within these three groups including Kaplan-Meier survival analysis. Risk factor analysis was performed by combining the complete and qualified success patients into one group and comparing them with the failures.

Results A total of 85 patients \18 years of age underwent Ahmed glaucoma valve implantation during the study period. Of these, 14 were lost to follow-up and were excluded from the final analysis. Patient demographics are provided in Table 1. The majority of patients had either PCG, JOAG, or glaucoma associated with angle anomalies; 15 eyes (21%), glaucoma in aphakia and pseudophakia; 47 eyes(66%), and glaucoma following penetrating keratoplasty;15 eyes (21%). More than one mechanism of glaucoma was present in some eyes. Of the eyes with primary congenital glaucoma, 9 had undergone penetrating keratoplasty prior to AGV implantation. Associated congenital anomalies were seen in 19 eyes (27%). The S-2 model was used in 44 eyes (62%); the FP-7 model, in 27 eyes (38%). The tube was inserted into the anterior chamber parallel to the iris surface in 64 eyes, into the ciliary sulcus in 3 eyes, and through the pars plana in 4 eyes. The scleral patch graft was secured in place in 69 eyes with 8-0 nylon sutures and in 2 eyes with fibrin glue. Visual acuity measurement was possible in 44 eyes (62%). The mean preoperative visual acuity was 0.79  0.45 logMAR and at the final follow-up was 1.21  1.07 (P 5 0.21). The reasons for decrease in visual acuity included graft failure in 5 eyes, phthisis in 3 eyes, retinal detachment in 3 eyes, and hypotony with choroidal detachment in 1 eye. IOP could be measured in 44 eyes (62%) on postoperative day 1. The mean IOP on the first postoperative day was 17.11  11.26 mm Hg (2–51 mm Hg). Five eyes (7%) developed hypotony and 8 (11%) presented with elevated IOP of .25 mm Hg on the first postoperative day (26 mm Hg to 51 mm Hg). IOP reduced from 35.86  9.57 mm Hg at baseline to 16.38  8.7 mm Hg at final follow-up (P \ 0.001; Figure 1), a mean decrease of 54%. There was a decrease in the number of antiglaucoma medications used from 2.42  1 preoperatively to 1.31  1.1 at the final visit (P \ 0.001). At the final

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Table 1. Baseline demographics of patients

Table 2. Details of previous glaucoma surgeries performed

Characteristic Age, months Mean Median Range Male:female OD:OS Follow-up, months Mean Median Range Glaucoma diagnosis Primary congenital/developmental glaucoma/ JOAG/glaucoma associated with ocular anomalies (phakic eyes) Glaucoma in aphakia and pseudophakia Post-traumatic glaucoma Uveitic Secondary angle closure glaucoma Silicon oil induced glaucoma Prior surgeries, median (range) Associated congenital anomalies Aniridia Peters anomaly Turner syndrome Microcornea and microphthalmos Choroidal coloboma Phacomatosis pigmento vascularis Congenital hereditary endothelial dystrophy Rubella Microspherophakia Corneal graft status Failed graft prior to surgery Clear grafts

82.07  58.31 72 2-204 40:31 36:35 37.79  32.11 27 3-126 15 (21.1%) 47 (66.1%) 2 (2.8%) 3 (4.2%) 1 (1.4%) 3 (4.2%) 2 (0-5) 4 (5.6%) 4 (5.6%) 1 (1.4%) 3 (4.2%) 1 (1.4%) 1 (1.4%) 2 (2.8%) 2 (2.8%) 1 (1.4%) 8 (54%) 7 (46%)

JOAG, juvenile open-angle glaucoma; OD, right eye; OS, left eye.

FIG 1. Scatterplot of intraocular pressure at baseline versus final follow-up.

follow-up, 51 eyes (72%) had an IOP between 6 mm Hg and 21 mm Hg; 44 (62%), an IOP between 6 mm Hg and 18 mm Hg; and 29 (41%), an IOP between 6 mm Hg and 15 mm Hg.

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Type of glaucoma surgery

Number (%)

External trab External trab 1 trabe with MMC Trabe with MMC, followed by at least one repeat trabe External trab followed by at least one trabe External trab 1 trabe with MMC followed by at least one trab Diode cyclophotocoagulation

4 (5.6) 4 (5.6) 24 (33.8) 10 (14) 6 (8.4) 12 (16.9)

MMC, mitomycin C; Trab, trabeculotomy; Trabe, trabeculectomy.

Ocular hypertensive phase occurred in 23 eyes (32%). The mean IOP in eyes with a hypertensive phase was 29.34 mm Hg (range, 23–47 mm Hg). The mean number of antiglaucoma medications used during this phase was 1.41 (range, 1-3). There was no significant difference in the incidence of the hypertensive phase between groups. No risk factors analyzed for the hypertensive phase (age, sex, baseline IOP, AGV model, lens status, number of prior surgeries, preoperative central corneal thickness) were found to be significant. The mean IOP at the final visit in the hypertensive group was not significantly different from the eyes that did not experience this phase (19  8.71 mm Hg vs 15.12  7.87 mm Hg; P 5 0.065); however, the number of glaucoma medications required at the final visit was higher in the hypertensive group (2.04  1.1 vs 0.92  0.13; P \ 0.001). There were no significant differences in the baseline demographics between those receiving either the S-2 or the FP-7 model, and no significant differences in the postoperative outcomes in terms of IOP control, development of a hypertensive phase, or the number of antiglaucoma medications. However, visual acuity was worse in those who received the S-2 implant (P \ 0.004). Because we shifted to the FP-7 implant after this model was available in the market, the follow-up was longer in those with the S-2 implant (P \ 0.001). The median number of intraocular surgeries involving conjunctival dissection performed prior to AGV implantation was 2 (range 0-5). Fifty patents (70%) had undergone 2 or more previous glaucoma surgeries (Table 2), including lensectomy and vitrectomy for congenital cataract (26 eyes [37%]), penetrating keratoplasty (15 [21%]), vitreoretinal surgery (4 [6%]), corneal laceration repair with lens aspiration in (2 [3%]), membranectomy (2 [3%]), corneal laceration repair with lensectomy with vitreoretinal surgery (1 [1%]), and extracapsular cataract extraction (2 [3%]). Details of glaucoma surgeries performed are mentioned in Table 2. The duration between previous intraocular surgeries and AGV implantation ranged from 1 to 173 months (median, 6 months). Most complications were transient and were managed conservatively (Table 3). Graft failure occurred in 5 of the corneal grafts (71%) that were clear prior to AGV implantation. Failure was due to tube-corneal touch in 2 eyes, to limbal stem cell deficiency in 1 eye, and to graft rejection episodes in 2 eyes.

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Table 3. Complications Time frame relative to surgery Intraoperative Iridodialysis Early postoperative (within 3 months) Blocked tube Tractional retinal detachment Vitreous hemorrhage Tube corneal touch Late postoperative (after 3 months) Tube corneal touch Phthisis Total retinal detachment Conjunctival dehiscence Tube block Corneal graft failure

Number (%) 1 (1.4) 3 (4.2) 1 (1.4) 2 (2.8) 1 (1.4) 6 (8.4) 3 (4.2) 2 (2.8) 2 (2.8) 1 (1.4) 5 (7)

Tube-related complications necessitated reoperation in 9 patients (13%): tube trimming in 4 patients, 1 of whom also needed anterior vitrectomy; tube repositioning in 4 patients, one of whom developed a retinal detachment and underwent intraocular lens (IOL) and AGV removal with vitreoretinal surgery; and implant removal after an attempted repair with a conjunctival and sceral patch graft in 1 patient, who had conjunctival dehiscence and tube erosion. One patient who developed a retinal detachment underwent successful surgery, retaining the implant. Nine eyes (13%) required retreatment for IOP control: repeat diode cyclophotocoagulation in 6 eyes and sequential AGV implantation in 3 eyes. Primary AGV implantation was performed in 23 eyes (33%). These were eyes in which trabeculectomy was deemed likely to fail: 11 eyes with aphakia following lensectomy and vitrectomy; 3 eyes that had undergone penetrating keratoplasty, of which 2 eyes were aphakic; 1 eye following a corneal laceration repair with lens aspiration; 5 eyes that had undergone vitreoretinal surgery, of which 2 had undergone multiple surgeries; 2 eyes that had undergone membranectomy with IOL removal; and 1 eye was pseudophakic. Complete success was achieved in 6 eyes (26%) and qualified success in 11 eyes (48%); 6 eyes (26%) failed due to uncontrolled IOP.

Subgroup Analysis Group 1 (PCG, JOAG, or ocular anomalies) included 15 eyes (21%); group 2 (glaucoma in aphakia and pseudophakia), 47 (66%); and group 3 (other diagnoses) 9 (13%). In group 3, 6 eyes had post-penetrating keratoplasty glaucoma, 1 had Sturge-Weber syndrome, and 1 had aniridia. Survival analysis for the entire group showed a success rate of 97% at 12 months and 80% at 24 months (Figure 2). Survival analysis showed a success rate of 100% in group 1, 95% in group 2, and 90% in group 3 at 12 months. This reduced to 82% in group 1, 86% in group 2 and 42% in group 3 at the end of 2 years (P 5 0.008 [log-rank test]; Figure 3).

FIG 2. Kaplan Meier survival analysis of the entire group. The number of patients at each follow-up interval is depicted in the table.

FIG 3. Kaplan-Meier survival analysis of the three groups.

Failures numbered 27 (38%). Causes for failure included uncontrolled IOP in 21 eyes, 9 of which required reintervention for glaucoma; absence of light perception in 1; implant removal in 1; phthisis in 3; and persistent hypotony in 1 eye. The reasons for phthisis included retinal detachment in 2 eyes and persistent hypotony with choroidal detachment in 1 eye. The parents of the last patient refused further surgical intervention for management of the choroidal detachment. The risk factors analyzed for failure included age at the time of AGV implantation, sex, baseline IOP, previous number of surgeries, model of the implant used, presence of a hypertensive phase and the diagnostic category. The only significant risk factor was diagnostic category (P 5 0.029).

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Discussion Glaucoma drainage devices offer a suitable option in the management of pediatric glaucoma. Success rates of 54% to 95% have been reported with the use of these devices in patients under 18 years of age.12-15 This variation in surgical results reflects the differences in the populations reported, including patient agethe type of glaucoma, the variations in technique, including the different types of devices used, the use of adjunctive agents to reduce conjunctival scarring, in the number of previous surgeries, as well as differences in the definitions of success and failure. The World Glaucoma Association guidelines for reporting success rates following glaucoma surgical procedures recommend several alternatives for an upper limit: #21 mm Hg, 18 mm Hg, 15 mm Hg, 12 mm Hg, and one for the lower limit, 6 mm Hg.16 Most published reports on the use of the AGV in pediatric eyes use an upper limit of 21 mm Hg to 23 mm Hg and a lower limit of \5 mm Hg with or without medications to define success, and report success rates of 70% to 94% using these definitions.12-15,17-20 In our series 51 eyes (72%) had successful control of IOP at the final visit using these definitions. Adjunctive use of antifibrotic agents have also been reported, with success rates of 80% to 90% with mitomycin C and 80% with the use of intraoperative subconjunctival Injection of bevacizumab (1.25 mg)15,17,19 We achieved success rates of 100% in group 1, 95% in group 2, and 90% in group 3 using our definition without the use of antifibrotic agents, at the end of 12 months, despite the fact that at least 70% of our patients had undergone more than two surgeries which involved conjunctival dissection earlier. A large proportion of our patients had also undergone penetrating keratoplasty prior to AGV implantation. The Ahmed valve implant incorporates a restrictive device to reduce the risk of postoperative hypotony and its related complications. Since children are at a higher risk for hypotony due to reduced ocular rigidity, one would expect reduced risk of early postoperative hypotension with this device. In our series only 5 eyes (7%) developed early postoperative hypotony. This could be an underestimation because IOP could be assessed by applanation tonometry in only 44 eyes (62%). Morad and colleagues12 reported hypotony in 14 eyes (23%) in their series, despite the use of a partial ligature of the AGV tube using 6-0 polyglactin sutures. Kirwan and colleagues18 used 20% concentration of Sulphahexachloride in their series of 19 eyes of 13 patients (all aphakic) to prevent hypotony. However, 2 eyes (11%) developed hypotony with choroidal detachment despite this procedure. A hypertensive phase during the postoperative period occurred in 23 eyes (32%) in our series. We were unable to identify any risk factors for the development of a hypertensive phase, which was not identified as a risk factor for failure in our series. The number of medications required to maintain successful IOP control was higher

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in our hypertensive group at the final visit, however. Nouri-Mahdavi and colleagues21 reported the occurrence of a hypertensive phase in 56% of eyes in their series of 139 patients (mean age, 60.1 years  21.4). Eyes with a hypertensive phase had a higher mean IOP and required more medications for IOP control than eyes without. Ayyala and colleagues22 defined a hypertensive phase as an IOP of .21 mm Hg for the first 6 months and reported this phenomenon in 70 eyes (82%) of their patients, of whom 48% were treated with medications alone and the rest with some form of surgical intervention. Ishida and colleagues23 reported better IOP control outcomes with AGV plates made of silicon than those of polypropylene. Our series was not sufficiently powered to identify a significant difference with regard to biomaterial of the plate. In our series, 15 eyes (21%) underwent penetrating keratoplasty, and graft failure occurred in 5 eyes of 7 (71%) with clear grafts at the time of surgery. Various risk factors have been identified for graft failure following implantation of drainage devices, including tube-corneal touch, mechanical trauma caused by eye rubbing, peripheral anterior synechiae formation around the tube, and multiple prior intra ocular surgeries.24-26 Tube-corneal touch, graft rejection, and limbal palisade deficiency were identified as causes of graft failure, in those who had clear grafts prior to surgery, in our series. Poor IOP control has also been previously identified as a risk factor for graft failure.26 Tube-related complications are the most common cause for reoperation following the implantation of drainage devices, with rates varying from 14.7% to 50% in the pediatric age group.13-15,27,28 Only 9 patients (12.6%) in our series required reoperation for tube-related issues. Endopthalmitis is also reported to be more common in the pediatric population, following the use of tube implants.29 None of our patients developed postoperative endophthlmitis. Risk factors identified for failure in the literature include previous surgery, surgical experience, and type of glaucoma as well as postoperative complications.13,19 The only risk factor identified in our study was categorization in group 3, of which the majority of patients (67%) was diagnosed with post-penetrating keratoplasty glaucoma. Our results are limited by the inherent biases of retrospective studies. Furthermore, the sample sizes of our groups 1 and 3 were small. Although 23 eyes (32%) underwent primary AGV implantation, 22 (95%) had undergone at least one surgery involving conjunctival dissection earlier. An advantage of our study, however, was the relatively long follow-up of at least 1 year for 64 eyes (90%) in our series. Only one eye per patient was included, thereby avoiding the bias of interocular correlation. In conclusion, the Ahmed glaucoma valve implant is a viable surgical option in treating pediatric glaucoma. At the end of 12 months, eyes in group 1 showed a success rate of 100%; in group 2, a 95% success rate. Eyes with post-penetrating keratoplasty glaucoma (group 3) were

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more likely to fail, both in terms of IOP control and maintenance of graft clarity. References 1. Broughton WL, Parks MM. An analysis of treatment of congenital glaucoma by goniotomy. Am J Ophthalmol 1981;91:566-72. 2. Gramer E, Tausch M, Kraemer C. Time of diagnosis, re-operations and long term results of goniotomy in the treatment of primary congenital glaucoma: a clinical study. Int Ophthalmol 1996-1997; 20:117-23. 3. Ikeda H, Ishigooka H, Muto T, Tanihara H, Nagata M. Long- term outcome of trabeculotomy for the treatment of developmental glaucoma. Arch Ophthalmol 2004;122:1122-8. 4. Beck AD, Lynch MG. 360 degrees trabeculotomy for primary congenital glaucoma. Arch Ophthalmol 1995;113:1200-202. 5. Mandal AK, Naduvulath TJ, Jayagnandan A. Surgical results of combined trabeculotomy-trabeculectomy for developmental glaucoma. Ophthalmology 1998;105:974-82. 6. Mullaney PB, Selleck C, Al-Awad A, Al-Mesfer S, Zwaan J. Combined trabeculotomy and trabeculectomy as an initial procedure in uncomplicated congenital glaucoma. Arch Ophthalmol 1999;117: 457-60. 7. Wallace DK, Plager DA, Snyder SK, Raiesdana A, Helveston EM, Ellis FD. Surgical results of secondary glaucoma in childhood. Ophthalmology 1998;105:101-11. 8. Iwach AG, Hoskins MD, Heterinton J, Shaffer RN. Analysis of surgical and medical management of glaucoma in Sturge-Weber syndrome. Ophthalmology 1990;97:904-9. 9. Beck DA, Lynn JM, Crandall J, Mobin-Uddin O. Surgical outcomes with 360-degree suture trabeculotomy in poor-prognosis primary congenital glaucoma and glaucoma associated with congenital anomalies or cataract surgery. J AAPOS 2011;15:54-8. 10. Sidoti PA, Belmonte SJ, Liebmann JM, Ritch RR. Effectiveness and complications of mitomycin C use in the treatment of pediatric glaucomas. Ophthalmology 2000;107:422-9. 11. Al-Hazmi Zwaan J, Awad A, Al-Mefsfer S, Mullaney PB, Wheeler DT. Effectiveness and complications of mitomycin C use during pediatric glaucoma surgery. Ophthalmology 1998;105:1915-20. 12. Morad Y, Donaldson CE, Kim YM, Abdolell M, Levin AV. The Ahmed drainage implant in the treatment of pediatric glaucoma. Am J Ophthalmol 2003;135:821-9. 13. Djodeyre MR, Calvo JP, Gomez JA. Clinical evaluation and risk factors of time to failure of Ahmed glaucoma valve implant in pediatric patients. Ophthalmology 2001;108:614-20. 14. Beck DA, Freedmann S, Kammar J, Jin J. Aqueous shunt devices compared with trabeculectomy with Mitomycin-C for children in the first two years of life. Am J Ophthalmol 2003;136:994-1000.

Volume 18 Number 4 / August 2014 15. Al-Mobarak F. Khan AO.Two-year survival of Ahmed valve implantation in the first 2 years of life with and without mitomycin-C. Ophthalmology 2009;116:1862-5. 16. Heuer DK, Barton K, Grehn F, et al. Consensus on definitions of success. In: Shaarway TM, Sherwood MB, Grehn F, eds. Guidelines on Design and Reporting of Glaucoma Surgical Trials. Amsterdam: World Glaucoma Association; Kugler Publications; 2009:17. 17. Mahdy RAR. Adjunctive use of Bevacizumab versus mitomycin-C with Ahmed valve implant in treatment of pediatric glaucoma. J Glaucoma 2011;20:458-63. 18. Kirwan C, O’Keefe M, Lanigan B, Mahmood U. Ahmed valve drainage implant surgery in the management of paediatraic aphakic glaucoma. Br J Ophthalmol 2005;89:454-8. 19. Pakravan M, Homayoon N, Shahin Y, Ali Reza BR. Trabeculectomy with mitomycin-C versus Ahmed glaucoma implant with mitomycin C for treatment of pediatric aphakic glaucoma. J Glaucoma 2007; 16:631-6. 20. Albis-Donado O, Gil- Carraso F, Romero-Quijada R, Thomas R. Evaluation of Ahmed glaucoma valve implantation through a needle generated scleral tunnel in Mexican children with glaucoma. Indian J Ophthalmol 2010;58:365-73. 21. Nouri-Mahdavi K, Caprioli J. Evaluation of the hypertensive phase after insertion of the Ahmed glaucoma valve. Am J Ophthalmol 2003;136:1001-8. 22. Ayyala RS, Zurakowski D, Smith JA, et al. A clinical study of the Ahmed glaucoma valve implant in advanced glaucoma. Ophthalmology 1998;105:1968-76. 23. Ishida K, Netland PA, Costa VP, Shiroma L, Khan B, Ahmed II. Comparison of polypropylene and silicone Ahmed glaucoma valves. Ophthalmology 2006;113:1320-26. 24. Ritterband DC, Shapiro D, Trubnik V, et al. Cornea Glaucoma Implant Study Group. Penetrating keratoplasty with pars plana glaucoma drainage devices. Cornea 2007;26:1060-66. 25. Stewart MKR, Battenburg M, Tole D, Larkin DFP, Kaye SB, NHSBT Ocular Tissue Advisory Group and Contributing Ophthalmologists. Effect of glaucoma on corneal graft survival according to indication for penetrating keratoplasty. Am J Ophtahlmol 2011;151:257-62. 26. Knape RM, Szymarek TW, Tuli SS, Driebe WT, Sherwood MB, Smith MF. Five-year outcomes of eyes with glaucoma drainage devices and penetrating keratoplasty. J Glaucoma 2012;21:608-16. 27. Coleman AL, Smyth RL, Wilson RM, Tam M. Initial clinical experience with the Ahmed glaucoma valve implant in pediatric patients. Arch Ophthalmol 1997;115:186-91. 28. Englert JA, Freedman SF, Cox TA. The Ahmed valve in refractory pediatric glaucoma. Am J Ophthalmol 1999;127:34-42. 29. Al-Torbak AA, Al-Shahwan S, Al-Jadaan I, AL-Hommadi A, Edward DP. Endophthalmitis associated with Ahmed glaucoma valve implant. Br J Ophthalmol 2005;89:454-8.

Journal of AAPOS

The use of Ahmed glaucoma valve in the management of pediatric glaucoma.

To assess the intraocular pressure control (IOP), changes in visual acuity, complications, reoperation rates and risk factors for failure following Ah...
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