Quantitative analysis of macular and peripapillary microvasculature in non-arteritic anterior ischaemic optic neuropathy

CLINICAL RELEVANCE: Non-arteritic anterior ischaemic optic neuropathy is a major cause of optic nerve dysfunction in older adults. Understanding its structural and microvascular consequences is essential for identifying disease susceptibility and guiding clinical monitoring. BACKGROUND: Non-arteritic anterior ischaemic optic neuropathy results from impaired perfusion of the optic nerve head, leading to permanent structural and vascular injury. Although clinically affected eyes show marked damage, fellow eyes may also demonstrate anatomical crowding and reduced vascular supply. METHODS: This retrospective observational study included eyes with chronic non-arteritic anterior ischaemic optic neuropathy, their unaffected fellow eyes, and age- and sex-matched controls. Structural parameters, including peripapillary retinal nerve fibre layer thickness, ganglion cell complex thickness, and optic disc morphology, were assessed using swept-source optical coherence tomography. Macular vessel density, radial peripapillary capillary plexus density, and inside-disc vessel density were evaluated using optical coherence tomography angiography. RESULTS: < 0.001), while fellow eyes demonstrated intermediate structural and vascular values. CONCLUSIONS: Chronic non-arteritic anterior ischaemic optic neuropathy is associated with persistent neuroaxonal thinning and microvascular reduction. Fellow eyes exhibit a disc-at-risk configuration and subtle peripapillary perfusion changes, suggesting bilateral anatomical susceptibility. Optical coherence tomography and optical coherence tomography angiography may help identify subclinical vulnerability and support longitudinal monitoring.