Ahmed Glaucoma Valve Implantation: Graft-Free Short Tunnel Small Flap versus Scleral Patch Graft After 1 Year Follow-up: a Randomised Clinical Trial

Purpose: To compare the efficacy and safety of graft-free short tunnel small flap (STSF) technique with that of scleral patch graft (SPG) in Ahmed glaucoma valve (AGV) implantation. Methods: Patients were enrolled and assigned randomly to STSF or SPG. Main Outcome Measures: tube exposure, Intraocular pressure (IOP), number of glaucoma medications, best corrected visual acuity (BCVA), surgical complications, and success rate ( defined as intraocular pressure (IOP) > 5 mmHg, ≤ 21 mmHg, and IOPreduction ≥ 20% from baseline at two consecutive visits after three months, no reoperation for glaucoma). Results: only one case in SPG developed tube exposure at 1-year follow-up. The cumulative probability of success during the first year of follow-up was 70% in the STSF and 65% in SPG (P=0.36). IOP decreased significantly from 29.6±8.6 mmHg at baseline to 16.4±3.6 mmHg at the final follow-up in STSF (p=0.001). The corresponding numbers for SPG were 30.9±11.2 and 15.8±4.7, respectively (p=0.001). The final IOP was comparable between both groups (p=0.65). Mean ±standard deviation of the number of glaucoma medications was 1.8±0.9 in STSF and 1.6±0.9 in SPG at final follow-up (P =0.32). Postoperative complications developed in 8 patients (19%) in STSF and 9 patients (23%) in SPG (P= 0.81). Conclusion: STSF and SPG techniques had comparable complication rate at one-year follow-up. Both techniques were comparable in terms of success rate, postoperative IOP, and glaucoma medications.