Reduced relative Ellipsoid Zone Reflectivity is associated with Ellipsoid Zone loss development and progression in Macular Telangiectasia Type 2

Abstract

Purpose : Disease staging in Macular Telangiectasia Type 2 (MacTel), a chronic progressive disease leading to photoreceptor damage in the central macula, has shown a significant association with the relative Ellipsoid Zone Reflectivity (rEZR). While this highlighted the value of the rEZR as a structural measure for photoreceptor integrity in optical coherence tomography (OCT), the prognostic value of the rEZR for the development and the growth of manifest EZ loss still needs to be identified.

Methods : MacTel patients demonstrating either development or progression of manifest EZ loss were retrospectively selected from a single center cohort of the natural history and observational registry study (NHOR). Areas of manifest EZ loss were manually delineated in en-face OCT imaging at each study visit. The rEZR was determined globally and topographically in volumetric OCT imaging of the baseline visit. Linear mixed-effects models were employed to assess the association of the rEZR and both the development and progression of manifest EZ loss.

Results : At total of 124 eyes from 83 patients (42 female, mean age 60.4 ± 8.83 years) were included with a median observational period of 32.8 [range: 0; 115] months. Out of those, 92 eyes of 63 patients demonstrated manifest EZ loss (mean ± standard deviation (SD) area: 0.412 ± 0.508 mm²) at baseline, while of the remaining 32 eyes (32 patients) 14 eyes showed development of manifest EZ loss at one of the follow-up visits (mean area: 0.070 ± 0.086 mm²). Mean EZ loss progression rate was revealed to be 0.079 ± 0.062 mm/month (square-root transformed). Lower rEZR values at baseline were shown to be a significantly higher risk for a future and spatially-confined EZ loss development given an odds ratio (OR) of 0.33, confidence interval [CI] 0.28; 0.38, p<0.001. Further, we found evidence that a decreased rEZR at baseline is associated with a faster EZ loss progression rate over time (coefficient estimate [CE] -0.0040; CI -0.0086 – 0.0006; p=0.085).

Conclusions : This study reveals the prognostic value of the rEZR for EZ loss development and its progression over time. The results underline the rEZR’s value as a biomarker for photoreceptor damage as well as eventually demise. Further longitudinal studies on a larger data set are warranted in order to better characterize the rEZR beyond manifest EZ loss in MacTel.

This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.