Optic Neuritis vs NAION vs Arteritic AION: How to Tell Them Apart
Last updated: October 2026
Short answer: optic neuritis typically affects young women with painful vision loss on eye movement and often a normal-looking disc. Non-arteritic ischaemic optic neuropathy (NAION) causes sudden painless loss, often on waking, in older patients with a small crowded disc. Arteritic AION (giant cell arteritis) causes severe loss with a chalky-white swollen disc in patients over 50 and is an emergency.
Side-by-side comparison
| Optic neuritis | NAION | AAION (GCA) | |
|---|---|---|---|
| Typical age | 20–45 years, more often women | Usually over 50 | Usually over 70 |
| Pain | Pain on eye movement in most patients | Usually painless | Headache, scalp tenderness, jaw claudication |
| Onset | Worsens over days | Sudden, often noticed on waking | Sudden, sometimes after transient visual loss |
| Severity | Variable | Mild to severe | Often severe (count fingers or worse) |
| Disc | Normal in about two-thirds (retrobulbar); mildly swollen in the rest | Segmental swelling, often hyperaemic; fellow eye has a small "disc at risk" | Chalky-white (pallid) swelling |
| Field defect | Central or diffuse | Altitudinal, often inferior | Altitudinal or severe diffuse |
| Key tests | MRI brain and orbits; consider aquaporin-4 and MOG antibodies in atypical cases | Blood pressure, diabetes, sleep apnoea screening | ESR, CRP, platelets; temporal artery biopsy or ultrasound |
| Treatment | IV steroids speed recovery (ONTT) but don't change final vision | No proven treatment; manage risk factors | Immediate high-dose steroids to protect the fellow eye |
| Prognosis | Most recover good vision | Limited recovery | Poor; high risk to the fellow eye if untreated |
Red flags for "atypical" optic neuritis
- No pain, very severe vision loss, or no recovery after several weeks
- Bilateral simultaneous involvement
- Marked disc swelling with haemorrhages or exudates
- Age over 50, or a background of systemic disease
- These should prompt testing for neuromyelitis optica (aquaporin-4 antibodies), MOG antibody disease, and infective or inflammatory causes.
Frequently asked questions
How do you tell optic neuritis from NAION?
Optic neuritis usually affects younger patients, causes pain on eye movement and worsens over days. NAION affects older patients, is usually painless and sudden, and shows segmental disc swelling with a small crowded fellow disc.
How do you rule out giant cell arteritis in ischaemic optic neuropathy?
Ask about headache, scalp tenderness, jaw claudication and systemic symptoms, and check ESR, CRP and platelets. A chalky-white swollen disc strongly suggests GCA. If suspected, start steroids immediately and arrange a biopsy.
Do steroids help NAION?
There is no proven treatment for NAION. Management focuses on risk factors such as blood pressure, diabetes and sleep apnoea.
Related: optic neuritis, giant cell arteritis, optic disc oedema and ONTT and IONDT.
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