Précis: Gonioscopy-assisted transluminal trabeculotomy (GATT) provides greater intraocular pressure (IOP) reduction in pseu- doexfoliative glaucoma (PXG) than in primary open angle glau- coma (POAG) in the first year of surgery; however, the difference between groups equalizes in the long term.

Purpose: To compare outcomes of GATT in eyes with POAG and PXG.

Methods: Single-center, retrospective, comparative case-series. A total of 202 eyes (91 eyes of POAG; 111 eyes of PXG) were included. GATT was performed as a standalone procedure or in combination with cataract extraction. Outcome measures were change in IOP and number of medications at all time points (1, 3, 6, 9, 12, 18, 24, and 36 mo after surgery), success rate (IOP reduction ≥ 20% from baseline or IOP between 6 and 21 mmHg, without further glaucoma surgery), and complication rate. Cumulative success probabilities were compared using Kaplan-Meier survival analyses.

Results: The mean IOP decreased by 8.8 mmHg (34.4%) in the POAG group with a mean decrease of 2 glaucoma medications at final visit. In the PXG group, the mean IOP decreased by 12.8 mm Hg (44.6%) on 2.3 fewer medications. Mean IOP reduction was significantly higher in PXG than POAG at all time points up to 2-year visit (P<0.05 for all), after which the difference was not significant. Cumulative success probability during the first year was significantly higher in PXG (97.6%) than in POAG (86.8%) (P=0.01); no significant difference was found at 2-year (P=0.07) and 3-year visits (P = 0.24).

Conclusion: GATT was safe and effectively reduced the IOP and medication burden in patients with POAG and PXG. In the first year after GATT, a significantly higher success rate was noted in PXG compared with POAG; however, in subsequent years, the success rate was similar at ~ 75%.

Key Words: gonioscopy-assisted transluminal trabeculotomy, pseudoexfoliative glaucoma, primary open angle glaucoma