Bleb Revision Using an L-shaped Conjunctival Flap Posterior to the Limbus in Eyes With Bleb Failure After PreserFlo MicroShunt Implantation.

Bleb fibrosis is a major cause of early surgical failure after PreserFlo MicroShunt implantation. Although needling is commonly attempted as first-line management, its effectiveness may be limited in cases with dense Tenon's encapsulation. The optimal surgical approach for open revision has not been well defined. This case series presents four consecutive eyes with bleb failure after PreserFlo MicroShunt implantation treated with revision using a fornix-based L-shaped conjunctival flap posterior to the limbus technique. Intraocular pressure (IOP), best-corrected visual acuity, corneal endothelial cell density, complications, and need for additional interventions were evaluated. The mean IOP decreased from 30.4 mmHg preoperatively to 9.5 mmHg at one month, 10.8 mmHg at three months, 12.5 mmHg at six months, and 13.4 mmHg at one year postoperatively. Visual acuity remained stable, and no clinically significant endothelial cell loss was observed. One transient choroidal detachment resolved spontaneously. One case required adjunctive topical glaucoma medication during follow-up; however, no patient required additional surgical intervention. Bleb revision using this posterior conjunctival flap technique effectively restored filtration and achieved sustained IOP reduction in eyes with bleb failure after PreserFlo MicroShunt implantation. By avoiding conjunctival dissection directly over the implant and minimizing limbal manipulation, this flow-redirection technique may preserve conjunctival integrity and represent a rational surgical alternative in selected cases.