The Value Of OCTA In The Diagnosis Of Non-arterial Anterior Ischemic Optic Neuropathy

Objective: To observe the superficial and deep capillary perfusion of optic disc in NAION eyes and normal contralateral healthy eyes;To observe the correlation between OCTA image,FFA and visual field of the affected eye,and to explore the application value of OCTA in the diagnosis of non-arterial anterior ischemic optic neuropathy.Method:Forty clinically diagnosed patients with acute phase NAION were included in this study.There were 40 eyes in the affected eye and 40 eyes in the normal contralateral healthy eye.The affected eye and the normal contralateral eye were divided into two groups,A and B.Patients with NAION were defined as acute phase with duration <3 weeks.Optical coherence tomography angiography(OCTA)was used to measure the superficial and deep capillary images of optic disc in NAION patients.The image was processed with ImageJ software by setting different thresholds to obtain the percentage of non-perfusion area of superficial and deep capillary blood flow around the optic disc.It was compared with the percentage of non-perfusion area of superficial and deep capillary blood flow of normal contralateral healthy eyes,and statistical analysis was conducted.The value of the superficial layer of optic disc was 105 um below ILM,and the value of the deep layer was 63-378 um below ILM.The early and late FFA images of the patients were analyzed,and the lesion sites of the patients were inferred by combining with the visual field examination,and the OCTA images were compared with the shallow and deep images.Results:There were 40 patients with monocular acute phase NAION.The percentage of non-perfusion area measured by OCTA in superficial and deepcapillary blood flow of optic disc was 9.68 ± 4.94 and 4.16 ± 2.53,respectively.The percentages of superficial and deep capillary blood flow non-perfusion area of the optic disc in normal contralateral healthy eyes were7.60±2.65 and 1.69±1.00,respectively.(t shallow =2.683,P =0.011;T deep layer =6.487,P < 0.0001);The results showed that the percentage of non-perfusion area of superficial and deep capillary blood flow in ipsilateral eyes was larger than that in healthy eyes.(t affected eye =11.231,P < 0.0001),(t healthy eye =14.895,P < 0.0001),the results were statistically significant.The percentage of non-perfusion area of superficial and deep capillary blood flow in the optic disc of all patients and contralateral healthy eyes was plotted by Medcalc software,The area under the ROC curve of perfusion free perfusion percentage in the superficial capillary blood flow of optic disc AUC=0.646,Jordan index =0.375,P =0.0249;The area under the ROC curve of the perfusion free perfusion perfusion percentage of the deep capillary blood flow in the optic disc AUC=0.826,Jordan index =0.625,P < 0.0001,It is of diagnostic value to measure the percentage of superficial and deep non-perfusion blood flow area of the optic disc in patients,and the value of deep diagnosis is better.OCTA images were interpreted to predict the coincidence degree between the lesion site of optic disc and the NAION lesion site of traditional clinical diagnosis such as FFA and visual field.A total of 27patients(67.5%,27/40)were diagnosed with the NAION lesion in OCTA superficial images.A total of 31 patients(77.5%,31/40)were presumed to have the same lesion site as NAION in OCTA deep images.FFA in patients with NAION :a.there were 6 eyes with low fluorescence at the early stage and high fluorescence at the late stage,accounting for 15%(6/40).B.16 eyes(16/40)showed low fluorescence at the early stage and high fluorescence at the rest of the late stage;C.In the early stage and late stage of the lesion,11 eyes showed low fluorescence,accounting for 27.5%(11/40);D.Early low fluorescence in the lesion site,and fluorescence leakage in the entire optic disc in the late stage.In the absence of relatively low fluorescence,a total of 7 eyes,accounting for 17.5%(7/40),were observed.Conclusions:1.In patients with non-arterial anterior ischemic optic neuropathy,the percentage of superficial and deep non-perfusion blood flow area of the optic disc of the affected eye is greater than that of the normal contralateral eye.2.The measurement of the percentage of the superficial and deep non-perfusion blood flow area of the optic disc is of diagnostic value for this disease,and the deep diagnosis value is better.3.Patients with FFA showed low fluorescence at the early stage of optic disc lesion,or high fluorescence at the late stage of optic disc lesion,or high fluorescence at the normal site,which corresponded to tortuous dilated vessels on the deep OCTA image.Low fluorescence at the lesion site in early stage,low fluorescence at late stage or low fluorescence at the whole optic disc was related to the lesion site,severity and duration of the disease.4.The decrease of the overall density around the optic disc in OCTA deep images may be related to the degree,range and duration of papillary edema.5.OCTA images can clearly observe the ischemia and compensatory sites in patients with NAION,which may partially replace FFA and other invasive tests in the future.