A consensus that exists because AION is managed inconsistently

Anterior ischaemic optic neuropathy is among the leading causes of sudden, painless, monocular vision loss in people over 50, and it is really two conditions sharing a name. The arteritic form, usually driven by giant cell arteritis, is a medical and ophthalmological emergency in which delay costs the fellow eye. The non-arteritic form is far commoner and has no specific effective treatment.

This joint position statement was produced by the vascular risk and systemic autoimmune disease groups of a national internal medicine society together with the national retina and vitreous society - the same collaboration that previously issued consensus documents on retinal arterial and venous occlusion. The stated reason for writing it is that management of AION remains heterogeneous, with considerable variation in care pathways, in how thoroughly a cause is sought, and in follow-up and secondary prevention. It reviews epidemiology, pathophysiology, diagnosis and treatment, and makes practical recommendations aimed at early detection, aetiological workup and prevention of visual and systemic complications, with particular emphasis on what the internist should be doing.

The authors are explicit that these are expert consensus recommendations, especially where high-quality evidence is absent - which is most of the non-arteritic territory. That honesty is what makes it usable. What it changes is not the treatment of either form but the pathway around them: whether a patient who arrives with sudden monocular loss gets a same-day inflammatory workup, whether anyone owns the vascular risk assessment afterwards, and whether ophthalmology and medicine are speaking to each other or sequentially seeing the same patient. In most units the honest answer to at least one of those is no.

• Treat sudden painless monocular loss over 50 as a possible arteritic event until inflammatory markers and history say otherwise
• Agree locally who owns the same-day pathway - ophthalmology, medicine, or both by protocol
• Do not let a non-arteritic diagnosis end the encounter; the vascular risk assessment is the intervention that remains
• Name which form you mean in every letter; 'AION' alone tells the next clinician nothing about urgency
• These are consensus recommendations, not evidence-based guidelines, and the document says so

Why it matters

The variation this document was written to address is in the pathway, not in the treatment - and pathways are fixable locally.

Don't overread it

Expert consensus rather than evidence-based guidance, as the authors state, particularly where evidence is lacking.

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