Glaucoma implants have been used for refractory glaucoma and are gaining popularity as a primary procedure in selected patients. In order to prevent tube erosion, a biologic material such as pericardium, cornea, and sclera is used as coverage over the tube. Despite this preventive measures, patch graft thinning and silicon tube exposure are still a serious complications and may occur in 1%-7% of eyes after glaucoma implantation. In this study we used a novel technique named short tunnel small flap (STSF) by tunneling the sclera without using any biological material . efficacy and safety of this technique is comparing with conventional scleral patch graft.

This randomized clinical trial, was performed at the Glaucoma Clinic of Labbafinejad Medical Center, Tehran, IRAN from September 2015 to January 2017 . The study was approved by the ethics committee at the Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran and followed the tenets of the Declaration of Helsinki. After explaining all therapeutic options and their side effects, the written consent form was obtained from all patient. 80 eyes of 80 patients with refractory glaucoma underwent AGV implantation by short tunnel small flap technique (group1) or scleral patch graft (group2) randomly. Primary outcome measure is Intraocular pressure(IOP) and Tube exposure, and secondary outcome measure is success rate that is defined as intraocular pressure (IOP) > 5 mmHg, ≤ 21 mmHg, and IOP reduction ≥ 20% from baseline at two consecutive visits after three months, no reoperation for glaucoma. Outcome measures are compared at 1, 3 , 6 and 12 months postoperatively.

Inclusion Criteria:

• Iranian patients with Caucasian ethnicity, and at least 25 years old who had inadequately controlled glaucoma.

Exclusion Criteria:

• Primary congenital glaucoma, thin sclera, no light perception vision, pregnant or nursing women, iridocorneal endothelial syndrome, epithelial or fibrous down growth, and unwillingness to participate in the study.