Purpose: To compare the volume of various spaces visible on optical coherence tomography (OCT) images in different angiographic lesion subtypes of neovascular age-related macular degeneration (AMD).
Methods: Sixty-six cases of previously untreated, active subfoveal choroidal neovascularization (CNV) associated with AMD were retrospectively collected. CNV lesions were classified as occult with no classic CNV, minimally classic CNV, predominantly classic CNV, or CNV lesions with associated retinal angiomatous proliferation (RAP). Corresponding OCT image sets were analyzed by trained graders using previously validated custom software that allows manual placement of boundaries on OCT B-scans. Spaces delineated by these boundaries included the neurosensory retina, subretinal fluid, subretinal tissue, and pigment epithelial detachments (PEDs). Volume measurements were calculated by the software and compared among groups.
Results: Minimally and predominantly classic CNV membranes demonstrated subretinal tissue on OCT in all cases and appeared to show a significantly greater volume of subretinal tissue than did the occult membranes. Subretinal fluid was present in all the predominantly classic cases. A PED was visible in all the occult CNV cases in our study, demonstrating less retinal thickening and significantly greater PED volumes than minimally and predominantly classic CNV lesions. Lesions associated with RAP showed the highest percentage of cystoid spaces.
Conclusions: OCT and angiography provide complementary information regarding CNV lesions. Quantitative analysis of OCT images allows for an improved understanding of the anatomic characteristics of angiographically defined CNV lesion subtypes.