What question did this study set out to answer?

This study aims to evaluate changes in photoreceptor integrity across different stages of diabetic retinopathy (DR) using a new imaging biomarker.

March 5, 2026Open Access

Evaluation of photoreceptor integrity in diabetic retinopathy using high-resolution optical coherence tomography

KHKim Lien HuberMedical University of Vienna DHDorota HimmelMedical University of Vienna ISI. SteinerMedical University of Vienna

Key Points

This study aims to evaluate changes in photoreceptor integrity across different stages of diabetic retinopathy (DR) using a new imaging biomarker.
Exploratory cross-sectional design with 64 eyes from 44 patients.
Used high-resolution spectral-domain OCT imaging for data collection.
Measured relative ellipsoid zone reflectivity (rEZR) across different DR stages within specific retinal areas.
Analyzed the association between rEZR, DR stage, and visual acuity using linear mixed models.
Significantly lower mean rEZR observed in proliferative DR compared to no DR and non-proliferative DR in the outer macular ring.
Total area rEZR was significantly lower in PDR compared to no DR and NPDR.
Peripapillary mean rEZR was significantly reduced in NPDR and PDR compared to no DR.
No significant differences found in the foveola, central 1 mm, or inner macular ring areas.

Abstract

Abstract Background The relative ellipsoid zone reflectivity (rEZR) is a promising imaging biomarker for photoreceptor integrity, but its variation across diabetic retinopathy (DR) stages remains unclear. This study investigates rEZR changes across different DR severities using high-resolution optical coherence tomography (OCT) imaging. Methods For this exploratory cross-sectional study, 64 eyes of 44 patients were included (17 eyes: no DR, 33 eyes: non-proliferative DR (NPDR), 14 eyes: proliferative DR (PDR)). Imaging was performed using high-resolution spectral-domain OCT (SPECTRALIS HighRes OCT, Heidelberg Engineering, axial resolution: 3 μm). rEZR (ratio between ellipsoid zone and external limiting membrane reflectivity) was measured at the foveola, within the Early Treatment Diabetic Retinopathy Study ETDRS grid (central 1 mm, inner ring, outer ring) and peripapillary. Linear mixed models assessed the association between rEZR, DR stage and visual acuity. Results In the outer macular ring, mean rEZR was significantly lower in PDR compared to no DR ( p = 0.005) and NPDR ( p = 0.045). In the total area, mean rEZR was significantly lower in PDR compared to no DR ( p = 0.016) and NPDR ( p = 0.032). Peripapillary mean rEZR was significantly lower in NPDR compared to no DR ( p = 0.013) and in PDR compared to no DR ( p = 0.033). No significant group differences were observed in the foveola, central 1 mm or inner macular ring. Conclusion Our data suggest that more advanced stages of DR are associated with a decrease in photoreceptor integrity, with statistically significant group differences predominantly observed in the outer macular regions and peripapillary.

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