Objective To develop and evaluate the rat model of chronic glaucoma by episcleral veins ligation (EVL). Methods Experimental glaucoma was induced unilaterally in 28 male Sprague-Dawley rats by ligating two episcleral veins. Intraocular pressure (IOP) in rats was measured by a Goldmann applanation tonometer under 3% pentobarbital sodium anesthesia. The optic nerve head and retinal vasculature were assessed by repeated fundus examinations. The amount of optic nerve axons was assessed by Image-Pro Plus image analysis system in a masked fashion. Results IOP without EVL was (19.21±1.23)mmHg, whereas the EVL eyes gained about 1.8-fold higher IOP [(33.96±2.73)mmHg] after EVL immediately (P