Surgical Outcomes of a Second Ahmed Glaucoma Valve Implantation in Asian Eyes with Refractory Glaucoma

Abstract

Introduction. When the initial glaucoma tube shunt fails in eyes with refractory glaucoma, one option is implantation of an additional Ahmed glaucoma valve (AGV) to control intraocular pressure (IOP). We aim to evaluate the outcomes of a second AGV in Asian glaucoma. Material and Methods. This is a retrospective interventional study, consisting of 21 eyes belonging to 20 patients which underwent a second FP7 AGV. Data collected included demographic characteristics, best corrected visual acuity, IOP, and number of medications. Both intraoperative and postoperative complications or interventions were recorded. The primary outcome measurement was success rate: complete success (IOP ≥5 mmHg and ≤21 mmHg without IOP-lowering medications) and qualified success (IOP ≥5 mmHg and ≤21 mmHg with IOP-lowering medications). Failure was defined as IOP ≥5 mmHg and ≤21 mmHg, reoperations for IOP-related indications, removal of second AGV implant, or loss of light perception. Postoperative complications were included as secondary outcomes. Results. The cumulative failure rates were 9.5%, 20.0%, 32.5%, and 46.0% at six months, one year, two years, and three years of follow-up. At final follow-up, complete success and qualified success rates were 23.8% and 33.3%, respectively; mean IOP and number of medications decreased by 5.6 mmHg (23.9%) and 1.7 mmHg (54.8%), respectively, from preoperative baseline (P<0.01). More common postoperative complications included hypertensive phase (38.1%), corneal decompensation (23.8%), and tube exposure (14.3%). Conclusion. An additional AGV implant had good short and modest long-term effectiveness in reducing IOP following a failed glaucoma tube shunt in Asian eyes, with the mentioned common postoperative complications to be actively monitored and managed.

Safety and Efficacy of Second Ahmed Valve Implant in Refractory Glaucoma

“…Tube-corneal touch was the leading cause of decompensation, and for this reason, tube shortening was performed in four patients, along with follow-up. Intraocular pressure spikes (25%) coincided with the hypertensive phase and could be related to the encapsulation of the bleb [26,31]. Three patients (11%) in our series developed a fibrotic capsule around the plate of the valve and did the revision.…”

“…Still, again the baseline IOP values of our population were higher (35.2 ± 7.9 mmHg vs. 23.4 ± 7.9) and our criteria of success were more stringent when compared to the one used by the authors. The first glaucoma drainage implant represents another difference because in our series, all patients underwent AGV, instead, in the paper published by Ong and co-authors, patients also underwent a Baerveldt implant in one case and in one patient it was not reported; moreover, looking at the glaucoma types, no cases of primary angle closure glaucoma were included despite the Asian race and primary open angle glaucoma cases being the most frequent [31]. Finally, regarding visual acuity during follow-up, this group validated our findings, but no significant difference in terms of BCVA was reported [31].…”

Reimplantation of a drainage valve device in refractory glaucoma. A clinical case

“…Наиболее широкое применение получил антиглаукомный клапан Ахмед, состоящий из тела дренажа и силиконовой трубки. В литературе сообщается об успешной имплантации дренажа Ахмед в 44,5-83,6% случаев [1][2][3][4][5]. Клапанный механизм дренажного устройства обеспечивает дозированный отток внутриглазной жидкости из глаза и активируется при давлении выше 10-12 мм рт.ст.…”

“…Несмотря на показанную краткосрочную эффективность имплантации клапана, долгосрочный успех первичной операции может быть ограничен вследствие высокой частоты инкапсуляции тела клапана у пациентов с рефрактерной глаукомой. В этих случаях возможно проведение ревизии зоны операции, однако при неконтролируемом ВГД показатели успеха варьируют в небольших пределах -от 25 до 42% [5,9,10]. В связи с этим одним из вариантов повторного хирургического лечения является имплантация второго клапана Ахмед, если первый имплантат не контролирует ВГД.…”

Surgical Outcomes of Glaucoma Drainage Device Implantation in Refractory Glaucoma Patients in Thailand

“…Hypotony occurred 2% of nonvalved GDD cases which was less than other studies. 15,16 These following procedures were used to attempt to control IOP in failure of GDD: implantation of the second GDD, which was reported to have a cumulative failure rate at three years of 32.5%, 22 transscleral cyclophotocoagulation procedure which was equally effective as the second GDD with cumulative success rates at one year of 88% and 79%, respectively 23 and needling revision of the glaucoma drainage device filtering bleb which were reported as 43% to 72.2% cumulatively for both complete and qualified success at 24 months. [24][25][26]…”