Quantitative Ellipsoid Zone Mapping and Integrity Assessment on Optical Coherence Tomography in the VISTA DME Study

Abstract

Purpose : To investigate the dynamics of ellipsoid zone (EZ) integrity on spectral domain optical coherence tomography (SD-OCT) in diabetic macular edema (DME) treated with intravitreal aflibercept injection (IAI) in the Phase III VISTA study.

Methods : This was a post hoc subanalysis of the IAI arms of the VISTA study. As per protocol, eyes were initially treated with five monthly 2-mg IAI and then either every 4 weeks (2q4) or 8 weeks (2q8). For this analysis, eyes imaged with the Zeiss Cirrus HD-OCT system were included. The 6 x 6 mm macular cube scan was analyzed for multiple time-points through week 100. Retinal OCT images were evaluated using a novel EZ mapping software platform with manual correction as needed to generate retinal layers for assessment of change in ellipsoid zone (EZ) parameters, including macular EZ-RPE volume and en face EZ integrity maps. Correlation analysis was conducted either with the Pearson correlation test or Spearman’s rank correlation test.

Results : A total of 106 eyes were included. EZ integrity was improved as measured by EZ-RPE volume (p=0.01) and reduction in EZ attenuation (p<0.001) in both the 2q4 and 2q8 groups. Central subfield EZ-RPE volume at week 100 directly correlated with final best corrected visual acuity (BCVA, p<0.01).

Conclusions : IAI resulted in significant improvement in EZ integrity metrics in both 2q4 and 2q8 groups. Central subfield EZ metrics exhibited the highest correlation with final BCVA. Future research is focused on identifying potential imaging biomarkers that may help predict functional and anatomic outcomes.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.