Objective: To describe a modified surgical technique, a scleral tunnel incision- trabeculectomy (STIT) and evaluate its safety and efficacy in lowering IOP in glaucoma patients.

Methods: One hundred and three patients were included in a retrospective, nonrandomized clinical study. Fifty-three patients were operated conventionally and 40 patients underwent STIT. In the modified technique the sides of the scleral flap are opened only half-way to the limbus and the flap is closed with a single releasable "slipknot"-suture.

Results: The mean IOP on the first postoperative day was 4.5 +/- 6.8 mmHg in the conventional group and 7.4 +/- 7.1 mmHg in the tunnel incision group (p = 0.012). On the second postoperative day the mean IOP was 4.5 +/- 7.3 mmHg and 6.3 +/- 6.5 mmHg in the conventional group and tunnel incision group, respectively (p = 0.065). There was no statistically significant difference in the mean postoperative IOP between the groups at one month and at 6-12 months. Shallow anterior chamber and iridocorneal touch occurred statistically significantly less in the tunnel incision group than in the conventional group.

Conclusions: STIT appears to be equivalent to conventional trabeculectomy (CT) in lowering IOP during the first 6-12 months postoperatively. It is also relatively safe and has fewer early complications related to excessive aqueous outflow than CT.