PAMM on OCT was seen in over a quarter of giant cell arteritis and never in NAION

Design

Retrospective observational study at two neuro-ophthalmology centres

Population

80 patients with biopsy-proven GCA and 179 with NAION

Primary outcome

Prevalence of PAMM on OCT

Effect

28% in GCA vs 0% in NAION (P < .001); 29% in GCA without visual symptoms

A retrospective study from two tertiary neuro-ophthalmology practices (British Journal of Ophthalmology, 30 September 2026) looked for paracentral acute middle maculopathy, a band of ischaemia in the middle retinal layers on OCT, in 80 patients with biopsy-proven giant cell arteritis and 179 with non-arteritic anterior ischaemic optic neuropathy.

PAMM was present in 28% of the giant cell arteritis group and in none of the NAION group. It appeared in 33% of those with persistent visual symptoms, 8% with transient symptoms and 29% of those with no visual symptoms at all. It persisted after steroids had been started, and was not linked to presenting acuity or field loss.

This turns a routine macular OCT into a useful clue. In an older patient with optic disc swelling, PAMM points strongly away from NAION. In a patient with suspected arteritis and normal vision, it can reveal retinal ischaemia that would otherwise be missed. Its absence does not exclude arteritis, because most patients with arteritis did not have it.

• Perform macular OCT in suspected anterior ischaemic optic neuropathy, and look for PAMM.
• Treat PAMM in an older patient with disc swelling as a strong pointer to giant cell arteritis.
• Do not use the absence of PAMM to rule out arteritis; about seven in ten patients with it had none.
• Do not delay steroids for imaging; PAMM persisted after treatment started, so OCT can be done afterwards.

Why it matters

It adds a quick, non-invasive test to the urgent question of whether a swollen disc is arteritic.

Don't overread it

A retrospective series from referral centres; specificity in routine practice needs confirming.

The statistics, in plain English

Finding PAMM in 0 of 179 NAION patients suggests very high specificity, but the true figure could still be a few per cent. Sensitivity was only 28%, so the sign helps when present and says little when absent.

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