Comparison of conjunctiva-related complications between scleral and corneal patch grafts in Ahmed glaucoma valve implantation.

Purpose: Comparison of the conjunctiva related complication rates and success rates among eyes with Ahmed glaucoma valve (AGV) implantation in which eye bank derived scleral and corneal patch grafts had been used to cover the tube.

Methods: Retrospective comparative study. Patients who underwent AGV implantation between January 2000 to December 2016 were included. Demographic, clinical data, intra and post operative data was obtained from electronic medical records. Conjunctiva related complications were divided into two groups: with and without implant exposure. Conjunctiva related complication rates, success rate, risk factors among eyes with corneal and scleral patch graft were compared.

Results: Three hundred and twenty three eyes of 316 patients underwent AGV implantation. Scleral patch graft was used in 214 eyes of 210 patients (65.9%) and corneal patch graft was used in 109 eyes of 107 patients (34%). Median follow up was 14 months. There was no significant difference in the conjunctiva related complication rate (7.3 % in corneal patch graft versus 7.0% in scleral patch graft;p=0.5) and conjunctival dehiscence rate (3.7% versus 4.6%, P = 0.7) among the two groups. Success rate was significantly higher in the corneal patch graft group versus the scleral patch graft group (98% versus 72%; p=0.001). Eyes with corneal patch graft had a higher survival rate (P = 0.01).

Conclusion: There was no significant difference in the rate of conjunctiva related complications following corneal and scleral patch grafts used to cover the AGV tube. Eyes with corneal patch graft had a higher success rate and survival rate.