When does the vision loss in NAION usually occur?

When does the vision loss in NAION usually occur?

• A. Lunch time
• B. Dinner time
• C. Upon awakening
• D. Before going to sleep

Answer: (C)

NAION presents with a sudden, painless loss of vision in one eye that is most often first noticed upon waking in the morning. The idea is that sleep brings a drop in blood pressure (nocturnal hypotension), which temporarily reduces blood flow to the optic nerve head via the short posterior ciliary arteries. That transient drop can cause ischemia, and the resulting vision loss is typically detected when the patient wakes up. This timing—upon awakening—fits the vascular-supply dynamics of the optic nerve head during sleep. The condition is nonarteritic and often occurs in eyes that have a structurally “at risk” optic nerve head (a crowded disk) and in people with vascular risk factors like hypertension or diabetes.

NAION presents with a sudden, painless loss of vision in one eye that is most often first noticed upon waking in the morning. The idea is that sleep brings a drop in blood pressure (nocturnal hypotension), which temporarily reduces blood flow to the optic nerve head via the short posterior ciliary arteries. That transient drop can cause ischemia, and the resulting vision loss is typically detected when the patient wakes up. This timing—upon awakening—fits the vascular-supply dynamics of the optic nerve head during sleep. The condition is nonarteritic and often occurs in eyes that have a structurally “at risk” optic nerve head (a crowded disk) and in people with vascular risk factors like hypertension or diabetes.