Histology does not provide a quantitative evaluation of the CNV lesion. Thus, we performed the following assay of the size of CNV by using choroidal flat mounts. Fourteen days after laser photocoagulation, mice were anesthetized and perfused through the left ventricle with a 26-gauge canula with 1 mL of 50 mg/mL FITC-labeled dextran in 10% gelatin (2 × 106 MW; Sigma, St. Louis, MO). The mice were killed by CO2 asphyxiation. The eyes were enucleated and fixed in 4% paraformaldehyde for 24 hours. The anterior segment, crystalline lens, and retina were removed from the eyeball. The remaining sclera, with choroid and retinal pigment epithelium, was flat-mounted after several relaxing radial incisions and cover-glassed. Specimens were analyzed by fluorescence microscopy (U-CMAD3; Olympus, Tokyo, Japan) in a masked fashion by a research assistant. WinROOF software (Mitani Corporation, Tokyo, Japan) was used to measure the size of the hyperfluorescent areas corresponding to CNV.