Changes in optic nerve head and macula optical coherence tomography angiography parameters before and after trabeculectomy

Purpose To evaluate the effects of lowering intraocular pressure (IOP) on foveal avascular zone (FAZ), peripapillary and macular vessel density (VD) by optical coherence tomography angiography (OCTA) in patients with open angle glaucoma after trabeculectomy. Study design Prospective study Methods Twenty eyes of 20 patients with primary open angle glaucoma (POAG) or exfoliation glaucoma (EG) who were followed up to six months and underwent trabeculectomy were included in our study. OCTA, AngioVue (Optovue Inc.) software was used to analyse the FAZ, peripapillary VD, macular superficial capillary plexus (SCP) and deep capillary plexus (DCP) VD. The parameters of the preoperative and postoperative controls were compared statistically. Results Twelve of the patients (60%) had POAG and eight (40%) had EG. Mean IOP measured was 22.4±2.4 mmHg preoperatively and 14.9±2.4 mmHg in the postoperative sixth month (p <0.001). There were no significant changes in OCTA optic disc and macular SCP VD values at the end of the sixth month. In macular DCP parameters; whole image VD (WI-VD), foveal VD (F-VD), parafoveal VD (PAF-VD) and perifoveal VD (PEF-VD) values increased statistically (p=0.003; p=0.026; p=0.006; p=0.004). There was a statistically significant decrease in FAZ area (FAZ-A) and FAZ perimeter (FAZ-P); and a significant increase was found in foveal density values (FD) (p=0.026; p=0.049; p=0.005). Conclusions We found that reducing IOP by trabeculectomy did not affect the microcirculation of the peripapillary region and macular SCP, while there was a significant increase in the DCP parameters of the macular region.