Prelaminar hyperreflective lines in non-arteritic anterior ischaemic optic neuropathy

To compare clinical and imaging features of non-arteritic anterior ischaemic optic neuropathy (NAION) with and without optic disc drusen (ODD)-like features, including ODD and hyperreflective lines (HRLs), and assess the impact of HRLs on disease outcomes.

This is a retrospective analysis of 17 NAION patients with ODD (ODD-AION), 25 NAION patients with HRLs only (HRL-AION), and 45 NAION patients without ODD-like features from a dataset of 177 NAION patients. ODD-like features were diagnosed via the enhanced-depth imaging optical coherence tomography (EDI-OCT). Patients underwent full ophthalmic assessment, including visual acuity, Humphrey visual field mean deviation, ganglion cell complex (GCC), retinal nerve fiber layer (RNFL), Bruch's membrane opening (BMO), and flavoprotein fluorescence (FPF) imaging.

ODD-like features were present in 23.7% of the NAION cohort and were associated with younger age at NAION onset and better visual acuity (adjusted p = 0.027), with higher GCC and RNFL thickness. BMO was significantly smaller in eyes with ODD-like features. ODD-AION showed earlier onset and female predominance, whereas HRL-AION resembled typical NAION demographically but had more favorable structural and visual outcomes. HRL-AION eyes demonstrated a lower global FPF signal when compared with NAION and ODD-AION.

Like ODD, the presence of HRLs in NAION is associated with crowding of the optic nerve head and better structural and functional outcomes, but not with a young onset of the disease. This study highlights the heterogeneity of NAION and the role of EDI-OCT findings in understanding determinants of outcomes.