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

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.

A Case Report Discussing The Options for Placement of Glaucoma Drainage Devices in the Presence of Corneal Decompensation

Purpose: The purpose of this case report is to discuss how the various placements of glaucoma drainage implants relate to corneal decompensation. Method: A 58-year Hispanic female presented for evaluation of decreased vision in the left eye for 2 years. This is a case report of a patient who underwent a secondary surgery to replace the anterior tube shunt implantation with a posterior shunt implantation following development of severe corneal decompensation. Results: Glaucoma tube shunt implants inserted into the ciliary sulcus of pseudophakic eyes shield the cornea offering protection against decompensation and avoid the risk of posterior segment complications. Conclusions: Placement of glaucoma drainage implants into the ciliary sulcus in pseudophakic patients with shallow anterior chambers, abnormal irido-corneal anatomy, or those at risk for corneal decompensation is a safe and effective method of not only lowering the intraocular pressure but also protecting the cornea against decompensation. As primary eye care providers, optometrists need to know the various treatment options and adverse effects associated with each procedure.

The use of collagen matrix (Ologen) as a patch graft in glaucoma tube shunt surgery, a retrospective chart review

Purpose: To determine the safety and efficacy of collagen matrix as a patch graft in glaucoma drainage surgery. Collagen matrix grafts may be advantageous because they do not need to be harvested from human donors. Methods: An institutional, retrospective review of 43 patients with at least 12 months follow-up status post-glaucoma drainage implant surgery were evaluated for signs of tube erosion after initial placement of collagen matrix patch graft. Results: Forty-one of 43 eyes (95.3%) required no intervention for patch graft melting with tube erosion. Average time of follow-up was 32 months (range: 12-45). Two cases had tube erosion at 4 months and 26 months post-op requiring tube revision, which was successfully revised with conjunctiva (4 month erosion) and donor sclera (26 month erosion). Conclusion: Our results suggest that collagen matrix patch grafts may be used successfully as a patch graft in glaucoma tube shunt surgery, and may be advantageous because they do not have to be harvested from human donors. It is possible that exposure rates may be higher after longer follow-up and with larger numbers of patients. Further research is needed to compare Ologen to traditional graft materials to conclusively determine the safety and efficacy of collagen matrix as a novel patch graft material.