Results of an Adaptive Surgical Approach for Managing Late Onset Hypotony After Trabeculectomy With Mitomycin C

Objectives:The objective of this study is to investigate the results of an adaptive approach of bleb revision surgery for late onset hypotony after trabeculectomy with mitomycin C because of bleb leakage and/or scleral melting.Methods:A total of 29 eyes of 27 patients, aged 63.811.7 years with hypotony maculopathy [intraocular pressure (IOP), 6mmHg] because of late onset bleb leakage and/or scleral melting after trabeculectomy with mitomycin C in which minimally invasive transconjunctival suturing of the scleral flap was impossible were enrolled in this retrospective interventional case series. External bleb leakage was seen in 16 eyes, 11 eyes suffered from scleral melting. Because of the intraoperative findings regarding appearance of conjunctiva and sclera 4 different surgical approaches were used: (1) bleb excision (in case of external leakage) and conjunctival reapproximation, (2) bleb excision and free conjunctival autografting, (3) human donor scleral patch grafting (in case of scleral flap defect) with conjunctiva reapproximation and (4) combined conjunctival and scleral patch grafting. Outcome measures were IOP and visual acuity (VA) development over time. Data analysis comparing changes in the parameters (IOP and VA) before and after bleb revision surgery was carried out using the paired t test.Results:Changes in IOP and VA were analyzed over 9.3 +/- 8.3 months (range, 1.1 to 36.5mo). IOP increased from 4.0 +/- 1.8mmHg, (P<0.001) before revision surgery to 13.1 +/- 4.1mmHg at 3 months after revision and 12.6 +/- 3.8mmHg at last follow-up visit, showing no significant difference in IOP between 3 months post revision and at the last documented patients' follow-up visit (P=0.28). The VA before revision surgery (0.42 +/- 0.28 logMAR) significantly increased (P=0.05) 3 months after revision (0.32 +/- 0.23 logMAR) and remained stable (P=0.65) until the last follow-up visit (9.3 +/- 8.3mo; range, 1.1 to 36.5) (0.35 +/- 0.32 logMAR).Conclusions:In patients with hypotony an adaptive approach of bleb management shows good results both in terms of IOP control and improvement in VA.