Differentiating Occult Neuroretinitis and Non-Arteritic Anterior Ischaemic Optic Neuropathy: Clinical and Optical Coherence Tomography Characteristics.

We report clinical and optical coherence tomography (OCT) differences among patients with occult neuroretinitis and non-arteritic anterior ischaemic optic neuropathy (NAAION). We retrospectively reviewed records of patients with a final diagnosis of occult neuroretinitis and NAAION seen at our institute. Data were collected regarding patient demographics, clinical features, concomitant systemic risk factors, visual function, and optical coherence tomography (OCT) findings at presentation and subsequent follow-up. Fourteen and 16 patients were diagnosed to have occult neuroretinitis and NAAION, respectively. Patients with NAAION were slightly older (median age 49, inter-quartile range [IQR]: 45-54 years, versus 41, IQR: 31-50 years) than patients with neuroretinitis. Seventy-five per cent of patients with NAAION were male versus 43% with neuroretinitis (p = 0.07). Systemic risk factors were present in 87.5% of patients with NAAION versus 21.4% in patients with neuroretinitis (p = 0.001). At presentation, all patients presented with blurred vision, had similar visual function, and had optic disc oedema. In addition, none of the patients had evident retinitis lesions, but 10 (71%) showed evident retinitis lesion at follow-up. Neuroretinitis patients had more often vitreous cells (64% versus 6%, p = 0.001), and subretinal fluid (78.6% versus 37.5%, p = 0.03) than the patients with NAAION. In summary, NAAION patients tended to be slightly older, more often male, and had associated systemic diseases more often than those with neuroretinitis. Neuroretinitis patients more often had posterior vitreous cells and subretinal fluid on OCT. However, larger prospective studies are needed.