Morphometric analysis of angiograms of exudative lesions in age-related macular degeneration

Objectives: To analyze the morphometric composition of lesion components in exudative age-related macular degeneration and to study the relationships between individual lesion components and choroidal neovascularization (CNV) subtype, at 2 time points. Methods: Morphometric analysis of 98 sets of angiograms separated by an interval of at least 3 weeks, with no treatment delivered in the intervening period between angiograms. Area measurements of individual lesion components were made from digitally captured angiograms. Choroidal neovascularizations were classified into subtypes based on the proportions of classic CNV. Fully corrected distance visual acuity measured on log-MAR Early Treatment of Diabetic Retinopathy Study charts was available at baseline and at a subsequent visit in 78 subjects. Data were analyzed using parametric and nonparametric tests, linear regression, and McNemar test of equal proportions. Results: Wholly and predominantly classic CNVs were significantly smaller at initial presentation than minimally classic or occult with no classic CNVs. Lesions containing blood and lipid were also significantly larger than lesions not exhibiting these features. Lesions containing any classic CNV expanded at a significantly greater rate than lesions without classic CNV. Approximately 40% of lesions categorized as wholly classic CNV converted to predominantly classic CNV between baseline and the next follow-up visit. Conclusion: The presence of classic leakage in exudative age-related macular degeneration is the most important risk factor for rapid expansion of CNV.