Retinal Vessel Density in Optical Coherence Tomography Angiography in Optic Atrophy after Nonarteritic Anterior Ischemic Optic Neuropathy

Aims. To compare optical coherence tomography angiography (OCT-A) retinal vasculature measurements between normal and optic atrophy after nonarteritic anterior ischemic optic neuropathy (NAION) subjects. Design. This prospective observational study was conducted between July 2015 and August 2016 at the ophthalmology outpatient department of a referral center in Taiwan. Peripapillary (4.5 × 4.5 mm) and parafoveal (6 × 6 mm) OCT-A scans were acquired. Measurements of the peripapillary region were obtained in two areas: (1) circumpapillary vessel density (cpVD) and (2) whole enface image vessel density (wiVD). Results. 13 participants with optic atrophy after NAION had lower peripapillary vessel density than the 18 age-matched participants in the healthy control (HC) group (p < 0.001 for both cpVD and wiVD). However, the parafoveal vessel density was not significantly different between the two groups (p = 0.49). The areas under the receiver operating characteristic curve for the HC and NAION eyes were 0.992 for cpVD and 0.970 for wiVD. cpVD and wiVD were significantly correlated with the average retinal nerve fiber layer thickness (p < 0.001 for both). Conclusion. Peripapillary retinal perfusion is significantly decreased in optic atrophy after NAION. OCT-A may aid in the understanding of structure-function-perfusion relationships in NAION.