Abstract
Purpose :
To evaluate foveal avascular zone (FAZ) and perfused vessel density changes after epiretinal and internal limiting membrane (ILM) peeling for epiretinal membranes (ERM) using OCT angiography (OCTA).
Methods :
This retrospective review included ERM patients imaged with OCTA (AngioVue SD-OCT,Optovue,Fremont,CA) before and after vitrectomy with membrane peeling from June 2016 to present. Patients with other ocular conditions were excluded, with the exception of mild cataract. Visual acuity (VA), central retinal thickness (CRT), FAZ metrics, and perfusion density in superficial (SPD), deep (DPD), and combined (CPD) capillary plexuses were compared pre- and post- operatively using 3mm and 6mm macular scans.
Results :
Fifteen patients (12 males) were included. Mean age was 70.3±8.0 years. Mean baseline VA (LogMAR 0.40±0.11) improved 6 and 12 months after surgery (0.30±0.15,p=0.07 and 0.22±0.16,p<0.01, respectively). Mean baseline CRT improved from 477.0±65.1μm to 420.8±57.9μm at 6 months (p=0.04) and 384.5±56.1μm at 12 months (p<0.01). Postoperative CPD was not significantly different in 3mm scans. In 6mm scans, CPD was 49.6±3.9% at baseline, 52.8±1.4% at 6 months (p=0.03), and 44.7±3.2% at 12 months (p=0.01). DPD was 43.6±3.5% at baseline, 47.3±4.3% at 6 months (p=0.02), and 45.4±5.1% at 12 months (p=0.58) for 3mm scans. DPD was not significantly different in 6mm scans. SPD was 47.0±4.7% at baseline, 42.0±5.6% at 6 months (p=0.03), and 41.7±3.2% at 12 months (p=0.06) for 3mm scans. In 6mm scans, SPD was 47.9±3.3% at baseline, 48.5±1.3% at 6 months (p=0.59), and 41.8±3.3% at 12 months (p<0.01). FAZ metrics were unchanged. Overall, VA gains did not correlate with perfusion density changes. However, patients with worse VA at 12 months (LogMAR >0.40) had a reduced mean CPD compared to those with better VA (51.9±2.4%, 47.4±2.4%, p=0.03) in 3mm scans. This was also seen in 6mm scans. Similarly, those with worse VA had increased CRT at 12 months (441.0±19.5μm, 363.3±50.1μm, p=0.03). This was also true at 6 months. FAZ measurements did not correlate with visual acuity or perfusion density.
Conclusions :
OCTA-angiography detected no difference in FAZ but significant changes in perfused capillary density postoperatively. This may represent structural remodeling after membrane peeling. A larger cohort or prospective study may enhance our understanding of postoperative changes in the retinal vasculature after ERM and ILM peeling.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.