Predilection of the Macular Region to High Incidence of Choroidal NeovascularizationAfter Intense Laser Photocoagulation in the Monkey

OBJECTIVE: To determine the key factors for creating a high incidence model of choroidal neovascularization (CNV) in the monkey. METHODS: Intense laser photocoagulation was performed in 8 eyes of 4 monkeys using krypton red and green-yellow and Alcon frequency-doubled diode ophthalmic lasers. Eight to 13 lesions were delivered to an area between the temporal vascular arcades in each eye. Development of CNV was monitored by fluorescein angiography at 2 and 4 weeks after laser treatment, and the results were correlated with histological analysis. RESULTS: A much higher incidence of CNV occurred in the macular region, which refers to an anatomic area equivalent to a mean +/- SD 2.5 +/- 0.4 times the horizontal diameter of the optic disc in the fundus. Regardless of the type of ophthalmic laser used, 72% of lesions developed fluorescein leakage within the macula, compared with 12% outside the macula (P<.001). By histological analysis, 89% of lesions developed microscopic CNV within the macula vs 22% outside the macula (P<.001). CONCLUSION: The macular region is predisposed to creation of laser-induced CNV in the monkey.Clinical Relevance The predilection of the macular region to a high incidence of laser-induced CNV may account for the high recurrence rate of subfoveal CNV after laser treatment in humans.