Glaucoma is closely related to elevation of intraocular pressure (IOP). Many studies have done on the effect of chronic elevation of lOP on the retina and optic nerve, but less attention was paid to the effect of acute elevated lOP. Here we briefly review experimental studies on functional changes of the visual system from the retina to the visual cortex under acute elevated lOP condition, which is similar to that of acute primary angle-closure glaucoma.