Evaluation of retinal vascular structure after epiretinal membrane surgery by optical coherence tomography angiography

Purpose To evaluate the retinal vascular structure before and after the epiretinal membrane (ERM) surgery by optical coherence tomography angiography (OCTA). Methods Twenty-two eyes with ERM (study eyes) had been evaluated by OCTA for superficial capillary plexus (SCP) and deep capillary plexus (DCP) vessel density (VD) at foveal and parafoveal regions and foveal avascular zone (FAZ) before and after ERM removal surgery. Twenty-two fellow eyes were selected as control group. Results Preoperative VD of SCP and DCP were significantly lower in ERM eyes than in controls in both foveal and parafoveal areas (p < 0.05, for all). The difference regressed in SCP (fovea: 18.04 +/- 3.1 vs 19.98 +/- 18p = 0.002 and parafovea: 47.33 +/- 3.54 vs 49.71 +/- 28p = 0.001), but persisted in DCP (fovea: 17.25 +/- 3.52 vs 17.57 +/- 4.01p = 0.856 and parafovea: 50.12 +/- 4.35 vs 50.93 +/- 3.24p = 0.791) in study eyes, postoperatively. Superficial and deep FAZ areas were significantly smaller in study eyes than controls. Postoperatively, superficial FAZ area enlarged (0.288 +/- 0.10 vs 0.307 +/- 0.08p = 0.012), whereas deep FAZ area did not (0.324 +/- 0.09 vs 0.338 +/- 0.07p = 0.435). FAZ area was correlated with the best-corrected visual acuity in ERM eyes. Conclusion Vascular damage in SCP and DCP was demonstrated by OCTA in eyes with ERM. ERM removal surgery mainly improves superficial changes caused by ERM. Changes in deep retinal flow may be associated with visual outcomes after ERM removal surgery.