Comparison of combined gonioscopy-assisted transluminal trabeculotomy and cataract extraction with gonioscopy-assisted transluminal trabeculotomy surgery alone on macular thickness.

Purpose: To evaluate the effect of Gonioscopy-assisted transluminal trabeculotomy (GATT) on macular thickness and to compare the combined GATT and cataract extraction (CE) with GATT surgery alone regarding macular thickness.

Methods: A retrospective, comparative study was designed. The patients who underwent GATT or combined GATT and CE with preoperative and regular postoperative spectral domain optic coherence tomography analysis (SD-OCT) were included. The macula was visualized in a 5 × 5 mm area by SD-OCT using MM5 mode. Two different groups were defined as follows: group 1 enrolled patients who underwent GATT alone, and group 2 enrolled patients who underwent combined GATT and CE. Pre- and postoperative macular thickness measurements by performing intragroup analysis and comparing group 1 with group 2 with regard to change in macular thickness were assessed.

Results: Fifty-four eyes fulfilled the inclusion criteria and were enrolled in this study, (Group 1 = 29 eyes, Group 2 = 25 eyes). The mean thicknesses of central macula (CM), superior inner macula (SIM), and nasal inner macula (NIM) significantly increased 1 month after GATT alone (p < 0.05). This difference became statistically insignificant at 3rd month after the surgery, (p > 0.05). The mean thicknesses of SIM, temporal inner macula (TIM), NIM, superior outer macula (SOM), inferior outer macula (IOM), and temporal outer macula (TOM) showed a significant increase 1 month after combined GATT and CE, (p < 0.05), which return its preoperative levels 3 months after the surgery (p > 0.05). There was no significant difference between group 1 and group 2 with regard to change in macular thickness at each time points, (p > 0.05). Postoperative clinically significant CME was observed in one patient who underwent GATT alone (p = 0.351).

Conclusion: GATT can be a safe procedure with minimal and transient adverse effect on macular thickness and structure. Performing GATT together with CE caused no additional increase in the risk of macular thickening.