Distribution of OCT Features within Areas of Macular Atrophy or Scar after 2 Years of Anti-VEGF Treatment for Neovascular AMD in CATT

Abstract

Purpose: Macular atrophy and scar increase in prevalence during treatment for neovascular age-related macular degeneration and are associated with poor visual acuity. We sought to identify the distribution of spectral-domain OCT (SD-OCT)-determined features and subretinal lesion thicknesses at sites of macular scar or atrophy after 2 years of treatment in the Comparison of Age-Related Macular Degeneration Treatments Trials (CATT).

Design: Cross-sectional analysis.

Participants: CATT participants with SD-OCT, color photographic (CP) and fluorescein angiogram (FA; CP/FA) images at year 2.

Methods: Sixty-eight study eyes at year 2 in CATT were selected based on image quality and CP/FA-determined predominant presence of the following: geographic atrophy (GA, n = 25), non-GA (NGA, n = 44), fibrotic scar (FS, n = 26), or non-FS (NFS, n = 7). The CP/FA components were delineated by CP/FA readers; SD-OCT morphologic features and thicknesses were delineated by OCT readers. Using custom software and graphic user interfaces, images were registered, overlaying features and components per pixel; differences were analyzed across groups.

Main outcome measures: OCT features, CP/FA components, and retinal and subretinal lesion thicknesses at each pixel of regional overlays.

Results: SD-OCT assessment of registered areas of pathology revealed the following: (1) retinal pigment epithelium atrophy (with or without residual lesion material) covered 75% of pixels designated as GA, 22% of NGA, 24% of NFS, and 46% of FS (P < 0.001). (2) Photoreceptor layer thinning covered 85% of GA, 42% of NGA, 33% of NFS, and 59% of FS (P < 0.001). (3) Subretinal lesion features covered 31% of GA, 42% of NGA, 85% of NFS, and 92% of FS (P < 0.001). Mean thickness of the subretinal lesion complex (measured in microns ± standard deviation) differed among GA (48±25 μm), NGA (61±35 μm), NFS (83±17 μm), and FS (151±74 μm) (P < 0.001). In eyes with GA, the thickness was greater in areas with residual lesion (51.4±27 μm) than in those without (27.2±9 μm).

Conclusions: Retinal pigment epithelium atrophy and photoreceptor layer thinning are common not only in areas of macular atrophy but also in areas of FS. Photoreceptor loss extends beyond the areas of clinically apparent atrophy and FS. Subretinal lesion components were common in areas of scar, but they were also present in nearly one-third or more of areas of macular atrophy.

Trial registration: ClinicalTrials.gov NCT00593450.

Figure 1.

Overlay of color photographic/fluorescein angiographic (CP/FA) designated characteristics and optical coherence tomography (OCT) designated features and thicknesses on aligned macular regions at the year 2 visit in CATT for an eye with predominant CP/FA designated geographic atrophy and predominant CP/FA designated fibrotic scar. GA = geographic atrophy, NSR = neurosensory retina, PED = non-drusenoid pigment epithelial detachment, RPE = retinal pigment epithelium, PRL = photoreceptor layer, SHRM = subretinal highly reflectively material, RPEDLC = RPE + drusen + lesion complex.

Figure 2.

Distribution among eyes of the mean thickness on optical coherence tomography (OCT) of the retinal pigment epithelium + drusen + lesion complex for the pixels within each color photograph (CP) /fluorescein angiographic (FA) component: GA = geographic atrophy, NGA = non-geographic atrophy, NFS = non-fibrotic scar, FS= fibrotic scar and NONE = macular areas without any lesion components. RPEDLC = retinal pigment epithelium + drusen + lesion complex. Box and whisker plots: Box upper and lower edges correspond to the 75th and 25th percentiles, respectively. Within the box, the circle corresponds to the mean value and the line corresponds to the 50th percentile (median). Ends of whiskers correspond to the lowest score within 1.5 times the interquartile range of the 25th percentile and the highest score within 1.5 times the interquartile range of 75th percentile. Each circle outside of the whiskers corresponds to outliers of the score.

Figure 3.

Distribution among eyes of the mean retinal thickness on optical coherence tomography (OCT) for the pixels within each color photograph (CP) /fluorescein angiographic (FA) component: GA = geographic atrophy, NGA = non-geographic atrophy, NFS = non-fibrotic scar, FS= fibrotic scar and NONE = macular areas without any lesion components. Box and whisker plots: Box upper and lower edges correspond to the 75th and 25th percentiles, respectively. Within the box, the circle corresponds to the mean value and the line corresponds to the 50th percentile (median). Ends of whiskers correspond to the lowest score within 1.5 times the interquartile range of the 25th percentile and the highest score within 1.5 times the interquartile range of 75th percentile. Each circle outside of the whiskers corresponds to outliers of the score.