The characteristics of optical coherence tomography angiography and its relationship with visual field defect in nonarteritic anterior ischemic optic neuropathy / 中华眼底病杂志

ABSTRACT

Objective To observe the blood perfusion of optic nerve and macular areas and investigate its relationship with visual field defect in nonarteritic anterior ischemic optic neuropathy (NAION). Methods Twelve consecutive unilateral NAION patients (course of disease <3 months) and 12 healthy Chinese adults were enrolled in the study. The affected eyes and fellow eyes from 12 NAION patients were defined as group A and group B; 12 eyes from 12 healthy adults were defined as group C. Best corrected visual acuity (BCVA), intraocular pressure (IOP), indirect ophthalmoscope and computer optometry were performed on all of the three groups of patients. Visual field (VF) and optical coherence tomography (OCT) were performed on NAION patients. Logarithm of the minimum angle of resolution (logMAR) was used to calculate visual acuity. Compared to group B, logMAR BCVA, mean deviation (MD) and pattern standard deviation (PSD) in group A were significant decreased (t=3.278, -4.909, 4.130, P<0.05). There was no significant difference in spherical equivalent, IOP, peripapillary retinal nerve fibre layer (pRNFL) between group A and group B (t=0.000, 0.890, 1.215; P>0.05). OCT angiography (OCTA) was used to measure the flow area (FA) at optic disc, flow area at radial peripapillary capillaries (RCFA) and FA, non-perfusion area (NFA), parafoveal vessel density (PVD) and parafoveal vascular index (PVI) in macular area. Pearson correlations between the deficiency of optic blood flow and visual field were analyzed. Results The differences of FA at optic disc and peripapillary RCFA among 3 groups were significant (F=4.162, 3.357; P<0.050). Compared to group B (t=-5.822, -7.467; P<0.001) and C (t=9.435, 4.615, P<0.05), FA at optic disc and peripapillary RCFA in group A was significantly reduced. There is several NAION showed quadrantal FA decreased in optic nerve. However, there was no significant difference in optic disc FA and peripapillar RCFA between group B and C (F=0.004, 0.030; P>0.050). There was no differences of FA, NFA, PVD and PVI among 3 groups (F=0.488, 1.107, 0.493, 1.086, 1.098, 0.093, 1.093, 1.221; P>0.05). Positive correlation between optic disc FA, peripapillary RCFA and MD (r=0.542, 0.585;P<0.05) were observed. However, there was no significant correlation between optic disc FA, peripapillary RCFA and PSD (r=-0.404, -0.430; P>0.05), and negatively correlated to BCVA (r=-0.617, -0.596; P<0.05). PRNFL was negatively correlated to optic disc FA (r=-0.643, P<0.05), but not correlated to peripapillary RCFA (r=-0.377, P>0.05). Conclusions The optic disc blood flow reduced in affected eyes of unilateral NAION whose disease course was less than 3 months, while the macular perfusion was normal. There was a positive correlation between optic disc flow and visual field.