Diseases causing sudden uni- or bilateral visual disturbance

1. Big picture

Sudden visual disturbance is a neurological and ophthalmological emergency until proven otherwise. In the exam, the first task is not to list every eye disease, but to answer three questions:

1. Is it monocular or binocular?

   • Monocular visual loss usually localizes anterior to the optic chiasm: eye, retina, optic nerve, ophthalmic artery, internal carotid artery.

   • Binocular visual field loss usually localizes behind the chiasm: optic tract, optic radiation, occipital cortex.

2. Is it transient or persistent?

   • Seconds to minutes, “curtain descending” → think amaurosis fugax / retinal transient ischemic attack.