Grading choroidal neovascular membrane regression after strontium plaque radiotherapy; masked subjective evaluation vs planimetry

To analyze angiographic changes in choroidal neovascular membranes (CNVM) after strontium-plaque (90Sr) irradiation for exudative age-related macular degeneration (AMD) using masked measurement of the CNVM areas and a masked subjective comparison of CNVM size and leakage. We studied the baseline, 3, 6, and 12-month angiograms of 19 eyes treated with 90Sr-plaque irradiation for exudative AMD. The area of CNVM-related hyperfluorescence was measured quantitatively, and the angiograms were subjectively evaluated by a masked grader. In 7 of the 19 eyes the CNVM-related hyperfluorescence was too scattered to be analyzed by planimetry but masked subjective grading correlated with the clinical response to irradiation. In the remaining 12 eyes, the CNVM decreased in size in 67% of the eyes and showed leakage in 67%. Planimetry and subjective assessment of the size and leakage of the CNVMs similarly reflected the regression after irradiation. CNVM size and leakage frequently diminish after 90Sr-plaque irradiation. Quantitative measurement of the CNVM areas, or a grading system based on masked subjective assessment, give similar results for evaluating these changes. Masked subjective grading can be used even in cases where the CNVM is too scattered to be outlined for planimetry.