Quantitative Outer Retinal OCT Metrics as Biomarkers for Predicting Geographic Atrophy Progression in Intermediate AMD – A 2-Year Progression Assessment

Abstract

Purpose : Advanced image analysis techniques, including machine learning-enhanced OCT segmentation and feature extraction, have revolutionized the characterization and assessment of dry age-related macular degeneration (AMD). This analysis aims to evaluate the association between quantitative OCT parameters and disease progression to geographic atrophy (GA) in eyes with intermediate AMD.

Methods : This IRB-approved longitudinal retrospective image analysis included eyes with baseline intermediate AMD. A machine learning-enabled feature extraction tool was employed to provide multi-layer segmentation [e.g. outer nuclear layer (ONL), ellipsoid zone (EZ), retinal pigment epithelium (RPE)] which was validated for every B-scan by a certified reader. Multiple outer retinal quantitative parameters were extracted, including EZ Integrity measures [total EZ attenuation (EZ-RPE = 0 microns), partial EZ attenuation (EZ-RPE ≤ 20 microns)] and ONL-RPE volume. A comparative analysis of metrics between eyes with stable intermediate AMD and those progressing to GA by year 2 was performed.

Results : 948 eyes were included in this analysis. After two years, 832 (87%) eyes remained classified as intermediate AMD, while 136 (13%) eyes developed GA. Of eyes that converted to GA, total EZ attenuation and partial EZ attenuation was significantly higher than in those who did not convert, 1.94% vs. 0.29% (p=1.90x10^-40) and 8.85% vs 1.72% (p=1.97x10^-43), respectively (Table 1). Additionally, eyes that converted to GA had significantly lower outer retinal volume on OCT, 3.998mm³ vs. 4.165mm³ (8.43x10^-7).

Conclusions : The identification of intermediate AMD eyes that are more likely to progress to GA is a critical need for being able to optimize and personalize care. The results of this analysis support previous studies that demonstrate that EZ integrity is highly associated with risk of progression to GA. Additional outer retinal metrics, such as ONL-RPE volume was also linked to GA risk. These findings offer valuable insights for clinical trial enrichment and the potential for targeted therapeutic interventions for higher-risk intermediate AMD patients.

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

 

Table 1: This table displays the mean values of several baseline Outer Retina metrics for two groups, one that developed GA and the other that did not, at a two-year follow-up period, along with a statistical comparison.