Effect of trabeculectomy on optic nerve head and macular vessel density: an optical coherence tomography angiography study

Purpose To investigate the effect of trabeculectomy on peripapillary and macular vessel density (VD) using optical coherence tomography angiography (OCT-A) in patients with primary open-angle glaucoma. Methods This is a prospective, interventional study on 32 glaucoma eyes (21 patients) who underwent trabeculectomy. Optic nerve head (ONH) and macular structural and OCT-A scans were performed before surgery and at one and six months postoperatively with the Avanti device (AngioVue System, Optovue Inc., Fremont, CA). The primary outcomes of interest were changes in global and regional peripapillary and macular VD. Results The average (standard deviation) age and visual field mean deviation of the sample were 58.9(9.9) years and −14.5(9.0) dB, respectively. The average (standard deviation) baseline intraocular pressure significantly decreased from 24.5(10.4) mmHg to 9.6(2.1) mmHg, 6 months after the surgery ( P < 0.001). The mean (standard deviation) whole image VD of ONH had increased from 37.6(8.3)% to 40.5(9.1)% at 6 months after the surgery ( P = 0.01) while its changes were not significant at month 1 (38.1(9.5)%, P = 0.64). The average of radial peripapillary circle (RPC) VD increased from 36.5(10.3)% to 39.3(10.8)% at 6 months ( P = 0.04) compared to 1-month post-trabeculectomy (37.0(11.4)%, P = 0.71). Similar patterns at postoperative months 1 and 6 were also observed in RPC VD at superior and inferior hemifields as well as nasal and temporal quadrants. The observed changes in VD of macular, foveal, peri-, and parafoveal were not significant at superficial or deep slabs at 1 and 6 months after trabeculectomy (all P values > 0.05). Conclusion Our study demonstrated significant improvements in peripapillary vessel density at 6-month following trabeculectomy.