Peripapillary and Macular Flow Changes in Nonarteritic Anterior Ischemic Optic Neuropathy (NAION) by Optical Coherence Tomography Angiography (OCT-A)

BACKGROUND: To analyze the blood flow changes of radial peripapillary capillaries (RPCs) and macula with time procession in patients with nonarteritic anterior ischemic optic neuropathy (NAION) by optical coherence tomography angiography (OCT-A). METHODS: A total of 21 affected eyes and 19 unaffected eyes from 21 NAION patients were included. Assessments of BCVA, CFP, SD-OCT, and OCT-A were performed on NAION patients at enrollment and at 1-2 weeks, 1-2 months, and 3–6 months after enrollment. Measures of the thickness of the peripapillary retinal nerve fiber layer (wRNFL) and macular ganglion cell complex (wGCC) of the whole image in SD-OCT, vessel density of the RPC (wRPC) and superficial and deep vascular complexes (wSVD, wDVD) in the whole image of OCT-A, and their superior- and inferior-hemi values (s/iRNFL, s/iGCC, s/iRPC, and s/iSVD) were assessed. RESULTS: Compared to unaffected control eyes, wRPC (p ≤ 0.001) was significantly lower in affected eyes at baseline, and there was no significant difference in wSVD (p > 0.05). The wRPC and wSVD values of affected eyes were significantly decreased at follow-up time points of 1–2 and 3–6 months compared to baseline (p=0.001, p ≤ 0.001; p ≤ 0.001, p ≤ 0.001). The sRPC values were significantly lower than iRPC at 1-2/3–6 months (p=0.016, p=0.013), and sSVD values were lower than iSVD at 1-2 months (p=0.010). Statistically significant correlations were found between wRPC and wRNFL values at 3–6 months (r = 0.626, p=0.022), between wSVD and wGCC at 1-2 weeks and 1-2 months (r = 0.570, r = 0.436; p=0.007, p=0.048). CONCLUSION: OCT-A revealed a sectorial reduction in vessel density in the RPC and macula with the disease progression of NAION from acute to atrophic stages, a classification associated with structural deficits.