Outer retinal band curvature strongly predicts late age-related macular degeneration (AMD) development

Abstract

Purpose : Integrity of the external limiting membrane, ellipsoid zone and interdigitation zone on optical coherence tomography (OCT) are emerging as strong predictors of late AMD development. However, they are often graded subjectively and a clinically translatable method of quantifying them is lacking. Recent work suggests the curvature of the retinal pigment epithelium or RPE sinuosity can be used to diagnose the early stages of AMD. This study assessed whether RPE sinuosity could also predict conversion to late disease in a high-risk AMD population receiving tertiary care.

Methods : Patients with intermediate AMD aged >50 years attending Vision Eye Institute, Chatswood (Sydney) between 2016-2023 were consecutively recruited if longitudinal macular OCT (Cirrus HD-OCT, Carl Zeiss Meditec, Dublin, CA) volume scans of quality scores >6 were available. Diagnoses were obtained from the clinical records and non-progressing patients were propensity score matched by age and sex. RPE segmentation and the RPE-fit line were automatically generated by proprietary software and the length of both lines was extracted using custom MATLAB code. RPE sinuosity was calculated as RPE:RPE-fit length (Figure 1). The prognostic ability of RPE sinuosity for predicting late AMD was calculated as adjusted odds ratios (ORs).

Results : Sixty-three converters and 57 converters with mean follow-up times of 33 and 31 months (p=0.60) were included. RPE sinuosity was 0.8% greater for converters than non-converters (p=0.003). The odds of developing late AMD per 1%, 2% and 5% increase in baseline RPE sinuosity was 1.66 (1.14-2.40), 2.75 (1.31-5.77) and 12.49 (1.95-80.09) after adjusting for age and sex.

Conclusions : RPE sinuosity was conveniently derived using existing software output and the odds of developing late AMD increased by 175% per 2% increase in curvature. RPE sinuosity could be used to refine prognostic models in AMD and improve patient management in high-risk populations.

This abstract was presented at the 2024 ARVO Imaging in the Eye Conference, held in Seattle, WA, May 4, 2024.

 

Figure 1: Automatic segmentations of the RPE (purple) and RPE-fit line (cyan) on baseline OCTs of eyes with iAMD who (A) progressed to late AMD and (B) remained stable over the follow-up period.