Prevalence of intraretinal and subretinal fluid in acute non-arteritic anterior ischemic optic neuropathy.

OBJECTIVE

This cross-sectional study aimed to characterise the prevalence and severity of intraretinal (IRF) and subretinal fluid (SRF) in in non-arteritic ischemic optic neuropathy (NAION).

METHODS

Two neuro-ophthalmologists assessed optical coherence tomography scans of patients diagnosed with acute NAION at a tertiary neuro-ophthalmology centre between July 2022 and July 2024 for peripapillary SRF, peripapillary IRF, and foveal SRF.

RESULTS

Sixty-eight eyes (median age 65.0 years, 32.4% female) were seen across a median follow-up of 10.6 weeks (interquartile range 5.8-28.5 weeks). Peripapillary SRF was present in five (7.4%) cases (height range 57.0-216.0 μm), peripapillary IRF in 32 (47.1%, height range 103.0-364.0 μm), and foveal SRF in six (8.8%, height range 51.0-288.0 μm). Peripapillary SRF did not extend beyond a quarter of the distance from the disc margin to the fovea, but peripapillary IRF extended more than halfway in 9 (28.1%) cases. Compared to patients without peripapillary IRF, patients with peripapillary IRF had a greater baseline pRNFL thickness (P = 0.02) and smaller CDRs in the unaffected eye (average CDR, P = 0.002). The presence of foveal SRF was associated with the presence of peripapillary IRF (P = 0.008), greater peripapillary IRF height (P = 0.003), and foveal peripapillary IRF extension (P = 0.003). The presence and severity of peripapillary SRF, peripapillary IRF, and foveal SRF were not associated with initial nor final visual function.

CONCLUSIONS

Peripapillary IRF restricted to the peripapillary region occurs in one-third of acute NAION cases but peripapillary IRF extending more than 50% to the fovea, peripapillary SRF, and foveal SRF are uncommon. Patients with smaller optic discs and more severe disc oedema may be more likely to develop peripapillary IRF and foveal SRF.