Quantitative study of vessel density in optic disc and macular region in patients with nonarteritic anterior ischemic optic neuropathy

Objective To evaluate the changes of vessel density in optic disc and macular in nonarteritic anterior ischemic optic neuropathy (NAION) patients based on optical coherence tomography angiography (OCTA).

Methods Thirteen monocular NAION patients with initial onset and disease course < 3 months were selected as the study objects 26 eyes in total, which were divided into affected eye group (n=13) and contralateral eye group (n=13). At the same time, 17 eyes of 17 healthy volunteers with matching gender and age were selected as healthy control group. All eyes were examined by OCTA, best corrected visual acuity and intraocular pressure. The density of all vessels and capillaries in the optic disc and the density of superficial capillary plexuses (SCP) and deep capillary plexuses (DCP) in macular were compared among the three groups.

Results Compared with the healthy control group and the contralateral eye group, the density of capillary and all vessels in the whole area and all sectors of optic disc in the affected eye group was decreased (P < 0.05). There was no significant difference in blood flow density between contralateral eye group and healthy control group (P>0.05). Compared with the contralateral eye group, the SCP density decreased in the affected eye group in the superior sector of perifoveal area, and DCP density was decreased in the superior, temporal and nasal sectors of paramacular fovea (P < 0.05). Compared with the healthy control group, the SCP density in the superior hemi-and nasal sectors in perifovea was decreased in the affected eye group(P < 0.05). There was no significant difference in blood flow density between contralateral eye group and healthy control group (P>0.05).

Conclusion The blood vessel density of macula and optic disc of NAION eyes decreases significantly, while the blood vessel density of contralateral eyes has no significant change. During the diagnosis, treatment and follow-up of NAION patients, clinicians should pay attention to the changes in optic disc blood flow and macular microcirculation in the affected eye.