Longitudinal Ellipsoid Zone Dynamics in Outer Retinal Integrity Following Epiretinal Membrane Surgery

Abstract

Purpose : Loss of ellipsoid zone (EZ) integrity is common in macular disorders, such as epiretinal membrane (ERM) and age-related macular degeneration. Recovery of EZ integrity follows therapeutic intervention, such as surgical removal of ERM. Limited data is available regarding the overall quantitative assessment of EZ dynamics following surgical intervention for ERM. The purpose of this analysis is to quantify EZ changes in integrity following ERM surgery.

Methods : This was a pooled IRB-approved retrospective image analysis of eyes undergoing ERM surgery from the prospective DISCOVER intraoperative OCT study and eyes undergoing traditional ERM surgery without intraoperative OCT. Inclusion criteria included a preoperative and postoperative OCT scan (6 or 12 months) of sufficient quality for quantitative analysis. The macular cube scans were imported into a multi-layer retinal segmentation platform with EZ mapping technology. Quantitative EZ features were extracted from each scan including, EZ-retinal pigment epithelium (RPE) thickness and volume parameters, a surrogate for photoreceptor outer segment length. En Face EZ-RPE thickness maps were assessed for percent partial attenuation (EZ-RPE thickness < 20 microns) and total attenuation (absence of EZ band).

Results : A total of 195 eyes were included in the study. Visual acuity (VA) improved from 20/53 at baseline to 20/29 postoperatively at 12 months (p<0.05). EZ attenuation improved from 2.37% (+/- 0.48%; SEM) at baseline to 0.42% (+/- 0.09%; SEM) postoperatively at 12 months (p<0.05). Similarly, total EZ attenuation improved from 2.22% (+/- 0.46%; SEM) at baseline to 0.29% (+/- 0.08%; SEM) postoperatively (p<0.05). Post-operative EZ-RPE central subfield mean thickness (CST), EZ-RPE central subfield volume (CSV), and EZ-RPE volume were not significantly different from baseline (p>0.05). EZ attenuation (r²=.311), EZ total attenuation (r²=.32), EZ-RPE CST (r²=-.29), EZ-RPE CSV (r²=-.28), EZ-RPE mid subfield volume (r²=-.29), and EZ-RPE volume (r²=.25) were significantly correlated with preoperative VA (p<0.05).

Conclusions : Longitudinal assessment of EZ features demonstrate significant postoperative improvement in multiple EZ integrity metrics following ERM surgery. Baseline quantitative EZ features correlated with baseline VA. Further research is needed to explore the relationship of EZ integrity factors to predicting functional surgical outcomes.

This is a 2020 ARVO Annual Meeting abstract.