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Sarah Thiele, Ben Isselmann, Maximilian Pfau, Robyn H Guymer, Chi D Luu; Natural history of the relative ellipsoid zone reflectivity in eyes with intermediate age-related macular degeneration. Invest. Ophthalmol. Vis. Sci. 2021;62(8):1938.
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The relative ellipsoid zone reflectivity (rEZR) on spectral-domain optical coherence tomography (SD-OCT) imaging is a potential indicator for photoreceptor’s health. The purpose of this study was to investigate the natural history of the rEZR in subjects with intermediate age-related macular degeneration (iAMD) and its association with high-risk factors of disease progression including reticular pseudodrusen (RPD) and pigmentary abnormalities (PA).
SD-OCT volume scans (49 B-scans, field size 20°x20°, collected every 6 months for 3 years) from an existing natural history cohort of AMD patients with bilateral large drusen (>125 mm) were used in this study. Using an automatic rEZR determination approach, the average rEZR of each raw SD-OCT volume was determined as the mean ratio of the ellipsoid zone (EZ) to the external limiting membrane (ELM) reflectivity (linear range of grey values: 0-1). The change in rEZR over 3 years was determined using linear regression models, adjusting for baseline age and the presence of RPD and PA.
A total of 145 eyes of 145 iAMD patients (mean age: 69.8 ± 8.1 years) were included, with RPD and PA being present in 30 (21%) and 37 (26%) eyes, respectively. At baseline, the average rEZR was lower in eyes with RPD (28.9 ± 15.5, arbitrary units, AU) compared to eyes without RPD (38.7 ± 17.2 AU, p = 0.005), however, there was no significant difference in rEZR between eyes with (33.6 ± 14.2) and without PA (37.8 ± 18.2, p = 0.208). Longitudinal analysis showed that rEZR was associated with age, the presence of RPD and PA. The rEZR linearly decreased over time and that the rate of change was significantly greater in eyes with RPD (-6.66 ± 2.2 AU per 6 months) compared to eyes without RPD (-0.73 ± 0.06 AU per 6 months, p<0.001), adjusted for age and the presence of PA at baseline.
The rEZR decreases over time and the rate of reduction is greater in eyes with RPD, a high-risk phenotype of progression, compared to eyes without. These findings warrant further studies evaluating the rEZR as a prognostic biomarker for progression to advanced AMD.
This is a 2021 ARVO Annual Meeting abstract.
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