A case-control study of peripapillary microvascular structure by OCT-angiography in non-arteritic ischaemic optic neuropathy at early and resolutive stages.

Objectives: To analyse peripapillary and papillary superficial microvascularization using OCT-angiography (OCT-A) in patients with non-arteritic ischaemic optic neuropathy (NAION) at the acute and resolutive stages.

Methods: This retrospective case-control study conducted between October 2018 and November 2019 included 23 NAION subjects at the acute stage (onset <1 month) and 20 patients at the resolutive stage (onset >3 months). NAION and contralateral eyes were compared to control eyes of patients (n = 50) matched 1:1 for refractive error, sex, age, systemic hypertension, diabetes, and sleep apnoea syndrome. The acquisition of OCT-A (OCTA-SD Cirrus 5000, Carl Zeiss) in 6 × 6 mm format centred on the papilla allowed measurement of the radial peripapillary plexus. A commercialized algorithm was used to obtain maps of density and microvascular retinal and papillary retinal perfusion, by positioning an ETDRS grid centred on the optic nerve head.

Results: There was significant decrease in peripapillary density and microvascular perfusion values for NAION eyes both at the acute and resolutive stages compared to the contralateral and control eyes, mainly in the temporal sectors. Papillary vascular density and perfusion were significantly increased in NAION and contralateral eyes compared to control eyes. There was no significant difference in peripapillary density or peripapillary vascular perfusion between contralateral and control eyes.

Conclusion: Eyes in the acute and resolutive phases of NAION exhibit decreased microvascular density and peripapillary capillary perfusion. Increased papillary vascular density and perfusion seem to be an intrinsic characteristic of the optic nerves of both eyes in patients who develop NAION.