Bleb reconstruction using donor scleral patch graft for late bleb leak and hypotony

Bleb dysfunction may occur as a late complication following glaucoma filtration surgery. Over-filtering, thinning and cystic blebs can lead to hypotony, leak and corneal dellen. We report our surgical management and outcomes of this specific entity using donor scleral patch grafts.

This is a 10-year non-comparative, retrospective interventional case series. Bleb reconstruction involved excision of encysted conjunctiva and sclera to identify the original fistula. A functioning donor scleral patch graft was sited over this with fixed and releasable sutures and the conjunctiva advanced. Intraocular pressure, visual acuity and post-operative issues were assessed.

A total of 18 eyes of 17 patients with mean age 65 years (standard deviation 13.5) were included. Trabeculectomy was the primary procedure in 72% (n = 13) and deep sclerectomy in 28% (n = 5). Bleb leak accounted for 61% (n = 11), hypotony 33% (n = 6) and corneal dellen 6% (n = 1). Mean pre-operative intraocular pressure was 7 mm Hg (standard deviation 4.6) which increased to 18.5 mm Hg (standard deviation 12) at day 1 (p < 0.001), 11.8 mm Hg (standard deviation 4.6) at 3 months (p < 0.05), 12.1 mm Hg (standard deviation 4.2) at 1 year (p < 0.01) which was maintained at 12.1 mm Hg (standard deviation 5.3) at last follow-up (p < 0.001). Post-operative interventions included bleb needling, re-suturing, suture removal, further glaucoma management, bleb leak and cataract surgery. Visual acuity also improved post-operatively and was maintained.

Reconstruction of the filtering bleb architecture with donor sclera results in improved intraocular pressure while maintaining visual acuity. Post-operative care is required to support the restored bleb function. Our findings support the use of scleral patch graft as an effective and safe method for the long-term management of hypotony and bleb leak as a late complication of glaucoma filtration surgery.