Author: Claude (AI), from PubMed abstracts · Reviewed by: Dr Mina Abdelmseih · Reviewed: 2026-11-15 · Review due: 2027-11-15

Educational content only. Not personalised medical advice. Clinical decisions remain the responsibility of the treating clinician.

Non-Arteritic Anterior Ischaemic Optic Neuropathy

Non-arteritic anterior ischaemic optic neuropathy (NAION) is the most common acute optic neuropathy in people over 50 and a major cause of blindness in this age group [S6] [S10]. It presents with sudden, painless loss of vision with a swollen optic disc [S2] [S10]. No treatment has been proven effective [S2] [S6] [S10], so care focuses on accurate diagnosis, risk factors and protection of the fellow eye.

Key points - Typical presentation: sudden-onset, unilateral, painless loss of acuity and field, with pallid disc swelling [S2] [S10]. - Risk factors include male sex, hypertension, hyperlipidaemia, diabetes, coronary heart disease and sleep apnoea [S4]. - Optic nerve decompression surgery gave no benefit in the only RCT and caused serious complications [S2]. Neuroprotective and steroid treatments remain unproven [S3] [S6]. - Vision often worsens early: 91.6% of eyes that progressed did so by day 8 of the trial, within 22 days of onset [S9]. - GLP-1 receptor agonists, especially semaglutide, are associated with a small increase in NAION risk in mainly observational data; decisions about these drugs should be shared [S7] [S8] [S11].

Evidence last checked: 2026-10-17 (PubMed abstracts).

Red flags

• Possible arteritic ischaemic optic neuropathy (giant cell arteritis) must be excluded urgently in anyone over 50 with optic disc swelling; see the giant cell arteritis article.
• Previous NAION in the fellow eye: the only consistent factor associated with progression of acuity and field loss [S9].
• Obstructive sleep apnoea, associated with progression [S9] and with NAION overall (risk ratio 3.28) [S4].
• Focal neurological signs or other atypical features: reconsider the diagnosis using history, examination and OCT [S10].

Recognise it

• Sudden, unilateral, painless visual loss with reduced acuity and field [S10].
• Risk factors (meta-analysis of 49 studies, more than 10 million patients): male sex (OR 1.67), hypertension (RR 1.28), hyperlipidaemia (RR 1.43), diabetes (RR 1.53), coronary heart disease (RR 1.68), sleep apnoea (RR 3.28) and factor V Leiden heterozygosity (RR 2.21) [S4].
• After cataract surgery: NAION risk is about four times higher within the first year (hazard ratio 4.6), mostly within 6 months, but absolute risk is low at 1 in 1,000 to 3,100 surgeries [S5].
• GLP-1 receptor agonists: a meta-analysis of 15 studies (more than 1.5 million patients) found odds ratio 1.70, with absolute risk 0.09% and number needed to harm about 2,700 [S8]. A semaglutide meta-analysis found hazard ratio 2.620, significant after 2 years of exposure [S7].

Confirm it

• Work-up includes history and examination with the relative afferent pupillary defect, visual fields and optical coherence tomography [S10].
• Use standardised acuity and automated perimetry to document a baseline; early progression is common [S9].

Manage it

Before acting on this section, check the national and local guidelines, product information and regulatory approvals that apply where you practise. See the medical disclaimer.

Tier A (primary care / no specialist)

1. Refer sudden painless visual loss in one eye to an eye service (timing: see Refer when); NAION is a major cause of blindness over 50 [S10].
2. Screen for and treat vascular risk factors and sleep apnoea, which are associated with NAION [S4]. Note that cardiovascular risk factors did not predict progression after onset [S9].

Tier B (general eye clinic)

1. Confirm the diagnosis with pupils, fields and OCT [S10], and consider arteritic disease (see Red flags).
2. Explain that there is no proven treatment [S2] [S10] and that vision may worsen over the first weeks: in trial sham eyes, 21.6% lost 10 letters or more by month 2 [S9].
3. Steroids: evidence of benefit in ischaemic optic neuropathy is insufficient and patients often have comorbidities that increase steroid adverse events [S3]. One quasi-randomised trial (60 patients, Germany) reported better acuity with fluocortolone plus pentoxifylline than pentoxifylline alone, but no field benefit [S1]. Do not treat routinely on this basis.
4. Do not refer for optic nerve decompression: in the only RCT (258 participants, stopped for futility), 29.4% vs 31.0% improved by 3 lines at 24 months, and surgery caused pain, diplopia and some cases of severe vision loss [S2].
5. Patients on GLP-1 receptor agonists: the North American Neuro-Ophthalmology Society and American Academy of Ophthalmology (2026, expert consensus) advise shared decision-making on whether to start, continue or stop [S11].

Tier C (specialist centre)

• Neuroprotection: intravitreal QPI-1007 (725 participants, sham-controlled) did not meet its primary end point; a subgroup with baseline acuity 20/63 or worse lost less vision [S6]. This is investigational.
• Fellow-eye counselling: discuss risk factors such as sleep apnoea [S4] [S9] and, before cataract surgery in the fellow eye, the low absolute risk [S5].

Refer when

Pitfalls

• Offering optic nerve decompression [S2].
• Overstating the GLP-1 risk: absolute risk is low and these drugs have mortality and cardio-kidney-metabolic benefits [S8] [S11].
• Assuming early worsening means a wrong diagnosis; progression usually occurs acutely [S9].

Evidence notes

• Conflict: the fluocortolone trial claims benefit [S1], while a review finds steroid evidence insufficient [S3]; the trial was small and quasi-randomised.
• GLP-1 evidence is mainly retrospective claims and health-record data; some studies show no association [S11]. Pooled RCT data were not statistically significant (OR 2.36, 95% CI 0.85 to 6.53) [S8].
• Risk-factor odds ratios are unadjusted [S4].
• The red flag and referral advice on giant cell arteritis has no source in this sheet: the Editor-in-Chief should link it to the giant cell arteritis article.
• Not covered by these sources: aspirin, phosphodiesterase inhibitors, nocturnal hypotension, the risk to the fellow eye in figures, and data from low- and middle-income countries.

Related articles

• Giant Cell Arteritis
• GLP-1 receptor agonists and the eye

References

See the numbered source list below. Each marker [S#] links to its PubMed and DOI record.