Materials and Methods: Patients who underwent GATT±phacoemulsification for primary open angle or pseudoexfoliative glaucoma and who were followed up for at least one year were divided into two groups as patients in whom anti-glaucomatous agents were continued in the postoperative period (Group 1) and anti-glaucomatous agents were discontinued (Group 2). Preoperative and postoperative ocular examination findings, mean retinal nerve fibre layer thickness (mRNFLT) by optical coherence tomography and mean deviation (MD) by standard automated perimetry were recorded. Pre/post-operative changes were analysed statistically within and between groups.

Results: Preoperative mean intraocular pressure (IOP) was 26.7±7.1 and 28.6±4.4 mmHg in groups 1 and 2, respectively (p=0.235). Central corneal thickness, iridocorneal angle and degree of pigmentation in the angle were similar between groups. The change in mean IOP at one-year follow-up was similar in both groups (p=0.087). There was no significant change in mean mRNFLT and MD for both groups in all postoperative measurements. Anti-glaucomatous medications decreased significantly in both groups at 12 months postoperatively, with significantly greater reduction in group 2 (p=0.032).

Conclusion: The findings of our study suggest that discontinuation of anti-glaucomatous agents after successful GATT ± phacoemulsification surgery has no effect on IOP change and disease progression in patients with mild-moderate open angle glaucoma. Nevertheless, it should be noted that postoperative follow-up should be performed appropriately as some cases may require reuse of anti-glaucomatous agents. Keywords : intraocular pressure, glaucoma progression, gonioscopy assisted transluminal trabeculotomy, open angle glaucoma