A method is provided for selectively occluding neovascular vessels formed in the ocular fundus of an eye, which includes intravenously administering a mono-L-aspartyl chlorin compound to a patient; subsequently estimating an appropriate time point when the mono-L-aspartyl chlorin compound has decreased in its concentration or has been eliminated from the retinal normal vascular vessels of the patient but is still remaining at an appropriate concentration in the vascular walls of the neovascular vessels of the ocular fundus; irradiating a laser light at a 664 nm-wavelength which is initiated at the appropriate time; and using the irradiation of the laser light to target lesions comprising the neovascular vessels, at a controlled power.