If blood supply to the optic nerve becomes blocked in some way, this can damage the nerve itself. There are four classifications of ischemic optic neuropathy. Transient visual obscuration results in vision loss episodes that last a few seconds and is due to intracranial pressure. Amaurosis fugax is a brief attack of blindness that can last for several minutes. Transient bilateral visual loss affects both cerebral hemispheres and causes serious vision loss. Finally, ocular ischemic syndrome involves constant ischemic damage to the eye, causing permanent vision loss.

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