The Use of Spectral-Domain Optical Coherence Tomography for Differentiating Long-standing Central Retinal Artery Occlusion and Nonarteritic Anterior Ischemic Optic Neuropathy

BACKGROUND AND OBJECTIVE: To report on the efficacy of macular and optic nerve spectral-domain optical coherence tomography (SD-OCT) in differentiating between long-standing central retinal artery occlusion (CRAO) and nonarteritic anterior ischemic optic neuropathy (NAION). PATIENTS AND METHODS: SD-OCT scans of the macula and optic nerve in 24 patients with unilateral optic atrophy secondary to CRAO (12 patients) and NAION (12 patients) were compared both qualitatively and quantitatively for differentiating features. RESULTS: In patients with long-standing CRAO, there was a significantly greater (P < .001) thinning of the macula relative to the fellow uninvolved eye (-59.7 ± 31.8 μm) compared to patients with longstanding NAION (-19.9 ± 8.4 μm) even though both conditions caused a similar (P = .726) degree of peripapillary retinal nerve fiber layer loss (-42.4 ± 18.5 μm and -44.1 ± 12.4 μm, respectively). CONCLUSION: SD-OCT macular scans can be used as an adjunctive tool for differentiating between longstanding CRAO and NAION.