Abstract
Purpose :
Using optical coherence tomography (OCT), numerous imaging biomarkers of retinal diseases can be generated – including thicknesses of individual retinal layers, which can be automatically extracted. In cross-sectional data from our AugUR study, we had observed an association between the thickness of the retinal pigment epithelium/Bruch membrane complex (RPE/BrM) and the photoreceptor layers with age-related macular degeneration (AMD). In this longitudinal analysis, we now investigated the prognostic value of these layer thicknesses for incident AMD.
Methods :
Within the baseline (BL) and 3-year follow-up (FU) of the population-based AugUR cohort study, recruiting individuals aged 70+, AMD was assessed using color fundus images and classified according to the Three Continent AMD Consortium Severity Scale. 49Raster volume scans of the macula were generated using a Heidelberg Spectralis OCT. Individual retinal layers were automatically segmented using standard tools from the Heidelberg Eye Explorer software, and thickness values in µm were exported. Logistic regression was performed to analyze the association of subfoveal thickness of the RPE/BrM, the outer nuclear layer (ONL), and the interjacent photoreceptor inner/outer segments plus interdigitation zone (PR-IS/OS) at BL with incident AMD. Analyses were conducted per person for the eye more severely affected by AMD at FU.
Results :
A total of 291 study participants without AMD at BL were included (age 76±4 years at BL, 46% female). Among these, 41 individuals developed AMD within the 3-year FU period (35 early, 6 late AMD). Mean thickness of the RPE/BrM at BL was 18.2±4.6µm (mean ± standard deviation) in those with incident AMD, versus 16.8±2.7µm in AMD-free individuals. A significant association was found between increased RPE/BrM thickness at BL and incident AMD (adjusted for age and sex: P-value=0.02; Odds Ratio=1.119; 95% confidence interval=[1.022, 1.226]). The two photoreceptor layer thicknesses were not significantly associated with incident AMD.
Conclusions :
An increased RPE/BrM thickness at BL was significantly associated with incident AMD – despite a limited number of cases. This suggests that retinal layer thicknesses, as quantitatively generated imaging biomarkers, may be capable of detecting changes that become recognizable as AMD on color fundus images three years later. Hence, they might also hold predictive and prognostic value.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.