Automated Evaluation of Choroidal Thickness and Minimum Rim Width Thickness in Nonarteritic Anterior Ischemic Optic Neuropathy

The aim of this study was to evaluate and compare peripapillary choroidal thickness (pCT) and macular choroidal thickness (CT), Bruch membrane opening-minimum rim width (BMO-MRW), retinal nerve fiber layer (RNFL) thickness, and optic disc area among nonarteritic anterior ischemic optic neuropathy (NAION) eyes, the contralateral unaffected eyes, and healthy control eyes. Twenty-six patients diagnosed with NAION (29 affected and 21 unaffected eyes) and 29 healthy matched control individuals (29 eyes) were analyzed by swept-source optical coherence tomography. All participants underwent scanning by Spectralis optical coherence tomography to analyze BMO-MRW, RNFL thickness, and optic disc area. Mean pCT in the NAION eyes, unaffected fellow eyes, and the control group was 130.5 ± 72.1 μm, 149.6 ± 75.7 μm, and 103.7 ± 36.7 μm, respectively (analysis of variance [ANOVA], P = 0.04). Mean macular CT in the NAION eyes, unaffected fellow eyes, and the control group was 226.1 ± 79.8 μm, 244.6 ± 81.4 μm, and 189.9 ± 56.4 μm, respectively (ANOVA, P = 0.03). Mean and all sectorial RNFL and BMO-MRW thickness values were significantly thinner in the NAION eyes vs the unaffected fellow and control eyes (P ≤ 0.00). The unaffected fellow eyes in NAION patients showed a significantly thicker average and sectorial BMO-MRW values than control eyes (P ≤ 0.02) except for the nasal sector (P = 0.09). Mean optic disc area derived from BMO analysis was not significantly different among groups (ANOVA, P = 0.86). The fellow unaffected eyes in patients with NAION showed significantly thicker mean peripapillary and macular choroidal and BMO-MRW thicknesses than disease-free control eyes. No differences in the mean optic disc area were found. Both a thick peripapillary choroid and a thick neuroretinal rim might contribute to the development of NAION or possibly be a secondary phenomenon.