NAION
Non-Arteritic Anterior Ischemic Optic Neuropathy
Plain-language definition
Sudden, painless vision loss from reduced blood flow to the front of the optic nerve. Most common acute optic neuropathy in people over 50.
Where this term comes up
“The more common form, NAION, has a different risk profile and no proven vision-restoring treatment.”
Condition · Ischemic Optic Neuropathy
“NAION (sudden vision loss): EMA classified NAION as a very rare potential side effect of semaglutide; U.S.”
Guide · GLP-1 Medications and Your Eyes: What Patients Need to Know
“The classic cause is ischemic optic neuropathy - non-arteritic (NAION) much more often, but the arteritic form from giant cell arteritis is a same-day emergency”
Finding · Altitudinal Visual Field Defect
- Category
- Condition, finding, or disease process
- Also written as
- No alternate forms listed.
Pathology terms describe diseases, tissue changes, exam findings, or complications that can affect vision or eye comfort.
Related glossary terms
A note on medical context
A glossary definition can explain a word, but it cannot tell you whether a symptom or test result is serious. If this term came from an article, use the full article and your clinician's guidance for context.