Background/aims

To evaluate quantitative changes in the foveal avascular zone (FAZ) area after glaucoma surgery using swept-source optical coherence tomography angiography (SS-OCTA).

Methods

Fifty-four consecutive patients with primary open-angle glaucoma (POAG) who met the inclusion criteria and underwent unilateral glaucoma surgery to reduce intraocular pressure (IOP) between April 2018 and July 2019.Eyes underwent IOP-lowering glaucoma surgery and their fellow (non-surgical) eyes were included. OCTA of the macula was performed in both eyes before glaucoma surgery and 3 months postoperatively. Two blinded examiners reviewed the image quality. Within- and between-group comparisons of the FAZ area and correlation of the FAZ area with age, IOP, central sensitivity and clinical variables.

Results

The mean (±SD) age was 66.7±11.3 years. After surgery, the IOP and FAZ area significantly decreased from 22.1±9.5 mmHg to 10.3±3.5 mmHg and from 0.485±0.193 mm² to 0.446±0.174 mm², respectively (both p<0.001). Conversely, in the non-surgery group, the preoperative and postoperative mean FAZ areas (0.398±0.119 mm² and 0.396±0.110 mm², respectively) did not significantly differ (p=0.469). Change in the FAZ area significantly correlated with the preoperative FAZ area, preoperative foveal sensitivity and change in IOP (all p<0.05).

Conclusions

The FAZ area is decreased with IOP-lowering surgery in patients with POAG, and change in the FAZ area was significantly correlated with both preoperative foveal sensitivity and change in IOP.