Non-arteritic ischemic optic neuropathy (NAION) is a neurological disease due to poor perfusion in optic disk. It causes severe visual function impairment, characterized by loss of vision and visual field defect. Optical coherence tomography (OCT) is vital for detecting anterior laminar depth, peripapillary nerve fiber layer thickness, ganglion cell complex thickness and peripapillary choroid thickness change in eyes with NAION at different course of the disease. In addition, OCT features are in accordance with visual function impairment. OCT angiography (OCTA) reveals retinal and choroidal vasculature networks in optic and macular area. OCTA revealed vasculature perfusion decline in eyes with NAION, even if their visual sensitivity and visual evoked potential were normal. Studying OCT and OCTA features is vital for exploring the pathogenesis and prognosis of NAION.
ObjectiveTo observe the blood perfusion changes of peripapillary and macular vessels in patients with nonarteritic anterior ischaemic optic neuropathy (NAION).MethodsRetrospective cohort study. Thirty-six eyes (19 affected eyes and 17 fellow eyes) of 19 patients with NAION diagnosed in People’s Hospital of Wuhan University from November 2017 to January 2019 were included in this study. There were 10 males and 9 females, with the mean age of 55.05±7.11 years. Forty eyes of 20 normal subjects matched with NAION patients were included as controls. BCVA, fundus color photography, SD-OCT and OCT angiography were performed in normal controls and repeated in NAION affected eyes at 1-2 weeks, 1-2 months, 3-5 months intervals. OCT quantitative measurements: average retinal nerve fiber layer thickness (aRNFL) of the disc and its superior values (sRNFL) and the inferior values (iRNFL), average ganglion cell complex thickness (aGCC) in macular region and its superior values (sGCC) and the inferior values (iGCC). OCTA quantitative measurements: average radial peripapillary capillary density (aRPC) and its superior values (sRPC) and the inferior values (iRPC), average vascular density of superficial retina (aSVD) in macular region and its superior values (sSVD) and the inferior values (iSVD), average vascular density of deep layer retina (aDVD), areas of foveal avascular zone (FAZ). The differences of OCT and OCTA quantitative measurements between NAION eyes and the fellow eyes and normal controls were comparatively analyzed. Independent sample t test, paired sample t test or nonparametric rank sum test were performed for comparison among three groups. Pearson or Spearman correlation analysis were used to analyze the correlation between RNFL and RPC, GCC and SVD, RNFL and GCC, RPC and SVD.ResultsAt baseline, the aRNFL, aRPC and aDVD of NAION patients were significantly higher than those of normal controls. Compared with the fellow eyes, the aRNFL increased significantly and the aRPC decreased significantly in NAION affected eyes. The overall differences of aRNFL, aRPC, aGCC and aSVD at four intervals within NAION affected eyes were statistically significant (P＜0.05). The average sRNFL, sRPC, sGCC and sSVD at 1-2 months interval were significantly lower than the average iRNFL, iRPC, iGCC and iSVD (P＜0.05). Correlation analysis: at 1-2 months interval, aGCC was positively correlated with aSVD (r=0.482, P=0.037); at 3-5 months interval, aRNFL was positively correlated with aRPC (r=0.631, P=0.037).ConclusionThere is a sectorial reduction of vascular density of peripapillary RPC and macular SVD with the disease progression of NAION.
ObjectiveTo determine the correlation between obstructive sleep apnea syndrome (OSAS) and nonarteritic ischemic optic neuropathy (NAION).MethodsIt was a perspective study. A total of 41 consecutive patients with NAION (NAION group) and 41 age- and sex-matched physical examination subjects (control group) in Xi’an No.3 Hospital from December 2016 to December 2018 were enrolled in this study. The apnea hypopnea index (AHI, the number of sleep apneas per hour) was monitored using a polysomnography for patients in NAION group and control group. At the same time, the blood oxygen saturation was continuously recorded. The OSAS can be diagnosed if the AHI value was ≥5. OSAS severity was graded as mild: 5≤AHI＜15; moderate: 15≤AHI＜30; severe: AHI ≥30. The grading of OSAS severity between two groups was compared by Fisher's exact test. The AHI and minimum blood oxygen saturation were compared between NAION group and control group using the Mann-Whitney U test. Spearman correlation analysis was performed on the correlation between OSAS and NAION.ResultsAmong the patients in the NAION group, 31 patients (75.61%) were diagnosed with OSAS. Among them, 6 patients (14.63%) were mild, 9 patients (21.95%) were moderate, and 16 patients (39.03%) were severe. In the control group, 19 patients (46.34%) were diagnosed with OSAS. Among them, 10 patients (24.39%) were mild, 5 patients (12.20%) were moderate, and 4 patients (9.75%) were severe. The difference of OSAS patients of mild, moderate and severe between two groups were statistically significant (Z=0.235, 0.245, 0.312; P=0.012, 0.014, 0.032). The average AHI of patients in the NAION group was 20.25±7.74, and the mean minimum oxygen saturation at night was (87.38±5.53)%. The average AHI of the control group was 18.67±11.67, and the mean minimum oxygen saturation at night was (85.06+4.25)%. The differences of the mean AHI and mean minimum oxygen saturation between two groups were statistically significant (Z=1.124, 2.317, P=0.003, 0.020). There was a positive correlation between OSAS and NAION (Spearman correlation coefficient=0.229, P=0.030).ConclusionThere is a positive correlation between OSAS and NAION.