Efficacy of Ab Interno Revision for Trabeculectomy Bleb Failure Using a Minimally Invasive Approach: A Prospective Study

Abstract

Précis: Ab interno bleb revision using the Grover and Fellman spatula offers potential benefits in improved intraocular pressure control and spare the conjunctiva for enhanced bleb management. Purpose: This study aimed to evaluate the safety and effectiveness of Ab-Interno Bleb Revision (AIBR) for treating failed trabeculectomy blebs. Methods: This non-comparative case series enrolled glaucoma patients with failed trabeculectomy blebs, who underwent AIBR and were followed up for one year. Eligible patients received subconjunctival Mitomycin C 0.1 mL of 0.2 mg/mL (20 μg) five days before the AIBR, performed using the Grover and Fellman spatula. The primary outcome measures were intraocular pressure (IOP) and the usage of IOP-lowering medications one year after the procedure. Secondary outcomes included the procedure’s failure rate and complications. Complete success was defined as achieving an IOP between 5–21 mmHg without medication, while qualified success required additional medical treatment. Results: The study comprised 23 eyes from 23 patients, having a mean age of 59.66±14.93 years. Preoperatively, the mean IOP was 23.54±10.7 mmHg, and the mean anti-glaucoma medication requirement was 3.99±0.65, both significantly reduced to 15.7±6.9 mm Hg (P=0.009) and 1.26±1.2 (P <0.001) at one year, respectively. Overall, 19 eyes (82.6%) achieved success (Complete success: 39.2%, Qualified success: 43.4%), while in 4 (17.4%) patients the procedure failed (IOP >21 mmHg). 5 patients had transient hyphema, but there were no sight-threatening complications such as hypotony or choroidal detachment. Conclusion: Ab-Interno Bleb Revision (AIBR) is a safe, effective, and minimally invasive intervention for managing failed trabeculectomy blebs. By eliminating the need to reopen the conjunctiva, this technique offers a promising alternative for the treatment of this challenging condition.