Outcomes of Prolene Gonioscopy Assisted Transluminal Trabeculotomy in Primary Open Angle Glaucoma and Pseudoexfoliation Glaucoma: A Comparative Study

Abstract

Précis: Gonioscopy-assisted transluminal trabeculotomy (GATT) provides greater intraocular pressure (IOP) reduction in pseudoexfoliative glaucoma (PXG) than in primary open angle glaucoma (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%.

Surgical outcomes of Gonioscopy-assisted Transluminal Trabeculotomy (GATT) in Primary and Secondary Open and Closed Angle Glaucoma

“…The results of this retrospective study demonstrate good surgical success rates as well as good IOP and medication reduction across a wide range of glaucomas, in a diverse population, in combination with lens extraction or as a standalone procedure. These results are in line with current literature on GATT 23 , which has been accumulating since the initial report by Grover et al 1 .…”

“…They reported a decrease of 8.8 mmHg (34.4%) and 12.8 (44.6%) in the POAG and PXG groups, respectively. Cumulative success at 1 year in POAG was 86.8% 23 , similar to our results in the combined and solo groups.…”

The Efficacy and Safety of the GATT Procedure in Open-Angle Glaucoma—6-Month Results

“…This researcher notes that in most cases of previous surgery, an extended opening of the canal was possible, which is similar to our observation. Cubuk et al [32] found that the results of GATT as the second procedure were better in PEXG than in POAG patients, which is similar to the results in naive patients [7].…”

“…The GATT technique introduced by Grover et al [6] consists of peeling the interior wall of the Schlemm's canal and perfectly matches the pathogenesis of IOP increase in glaucoma, which is related to the enhanced outflow resistance at this site. Since its introduction, the application of the GATT technique has been described in different types of glaucoma [7][8][9][10].…”

Is GATT the Answer?

“… 9 Patients with pseudoexfoliative glaucoma (PEXG) seem to have more favorable success rates (79%) compared to primary OAG (POAG) (73%); however, the difference was not statistically significant at the end of the 3rd year. 10 Future glaucoma research focuses on restoring the functionality of the TM and also the distal outflow system. Patients who have undergone GATT or have already dysfunctional distal outflow may just, therefore, become ineligible for these therapeutic options.…”