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

Abstract

Abstract: : Purpose: 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 the macaca fascicularis monkeys using krypton red, green/yellow and diode double frequency ophthalmic lasers. Eight to 13 lesions were delivered into an area between the temporal vascular arcades in each eye. Development of CNV was monitored by fluorescein angiography at 2 and 4 weeks post-laser treatment and the results were correlated with histological examination. Results: Intense photocoagulation with krypton red, green/yellow and diode double frequency ophthalmic lasers resulted in 15 %, 27 % and 58 % incidences of lesions showing fluorescein leakage, respectively (averaged 31 %). Further detailed analysis revealed that a much higher incidence of CNV occurred in the anatomic macula, which refers to an area equivalent to 2.5 ± 0.4 times the horizontal diameter of the optic disc. Fluorescein leakage occurred in 72 % lesions inside the macula compared with 12 % outside the macula (P=0.0005, unpaired t-test). Histology revealed that 89 % lesions inside the macula developed microscopic CNV versus 22 % outside the macula (P=0.00002, unpaired t-test). Conclusions: The macular region is highly predisposed to the incidence of laser-induced CNV in the monkey and this technique may be useful in the assessment of treatment modalities for CNV.

Keywords: choroid: neovascularization • laser