Purpose:
To identify, with high-resolution SD-OCT, morphologic alterations in eyes with geographic atrophy (GA) due to age-related macular degeneration (AMD) that correlate with the area of atrophy, rate of progression, and the presence of unifocal or multifocal patches of atrophy.
Methods:
Forty-three eyes of forty-three patients with AMD-associated GA without evidence of previous or current choroidal neovascularization at baseline were visualized by SD-OCT and fundus autofluorescence (FAF) imaging. Examinations with both imaging techniques were performed 24 and 48 weeks after the screening visit. The baseline area of GA as well as progression rates over a period of at least 24 weeks were calculated from the FAF images. Morphologic alterations on SD-OCT were evaluated in the baseline images.
Results:
Morphologic alterations that were more prevalent in large areas of GA than in small areas of GA included dome-shaped elevations of the outer retina in the perilesional zone (P<0.0001), irregular elevations of the outer retinal layers within the area of atrophy (P=0.0012), debris beneath these elevations (P=0.076), and outer retinal tubulations within the area of atrophy (P=0.072). Hyperreflective plaques in the outer retina, both at the junction between GA and non atrophic retina as well as in the atrophic region itself, were commonly seen in eyes with multifocal GA but appeared infrequently in eyes with unifocal GA (P=0.039). Morphologic alterations that occurred more commonly in faster progressing lesions than in slower ones included irregular elevations of the outer retinal layers within the area of atrophy (P<0.0001) as well as outer retinal tubulations within the area of atrophy (P=0.0055). When square root transformations were applied to the lesion area, separation of the outermost hyperreflective band occurred more frequently in faster progressing lesions than in smaller ones (P=0.0055).
Conclusions:
SD-OCT is a valuable tool for clinicians and researchers to visualize phenotypic variability in GA due to AMD. Distinct morphologic alterations visible in these eyes with SD-OCT are associated with large areas of GA, fast progression rates, and multifocal patches of GA. This information provides new insight into the pathogenesis and natural history of the disease and may be useful to evaluate the therapeutic benefits of interventions to slow the progression of the disease.
Clinical Trial:
http://www.clinicaltrials.gov NCT00950638
Keywords: age-related macular degeneration • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)