| Objectives:This paper explors the consistency of the three imaging diagnoses of different course of NAION patients.By describing the performance of non-arteritic anterior ischemic optic neuropathy(NAION)with different courses in three different examinations: fundus fluorescein angiography(FFA),visual field(VF)and optical coherence tomography angiography(OCTA).Methods:We collected 51 patients(61 eyes)who were diagnosed as NAION in the Ophthalmology department of the Affiliated Hospital of Yunnan University from February 2020 to March 2022.All patients were divided into three groups: the monocular acute stage group(group A),the monocular chronic stage group(group B),and the bilateral group according to the course of disease(group C).All patients were examined by FFA,visual field and OCTA according to the set standards,and all relevant examination data were collected.All results were analyzed by the following methods: 1.All imaging data were interpreted,and the characteristic imaging results of the three examinations were recorded.The optic disc was divided into four regions:superior,inferior,nasal and temporal.All three examinations use this standard to evaluate the ischemic region of the optic disc.2.Angio Tool was used for OCTA image processing and analysis to obtain the large vascular area and capillary density in and around the optic disc of patients of the affected eyes and the contralateral healthy eyes.The vascular parameters of the affected eye and the unaffected eye were compared.3.The correlation between the vascular parameters and the visual field parameters: the men defect(MD),the pattern standard deviation(PSD)was analyzed.4.The consistency of interpreting ischemic areas between two of the three examinations was analyzed.The statistical methods of comparative vascular parameters mueasured by OCTA use SPSS software for paired-sample T test.The correlation between MD value and PSD of the visual field and the vascular parameters of optic disc was analyzed by Spearman linear regression,and the consistency between FFA and OCTA was analyzed by Kappa.The difference was statistically significant if P was less than 0.05.Results:1.Imaging characteristics of FFA in monocular disease groupIn group A,82.86% of the patients had early optic disc telangiectasia and with the optic disc fluorescence leakage at late stage,while in group B,72.72% had early optic disc low fluorescence and optic disc fluorescence enhancement at late stage;In patients with retinal vein filling retardation,62.89% of the patients in Group A and72.72% in Group B had retinal vein filling retardation,and all patients had retinal vein routing areas consistent with the low fluorescence areas of the optic disc;According to the analysis of ischemic regions displayed by FFA,28 patients(80%)in Group A and 10 patients(90.9%)in Group B had the highest percentage of ischemic region in superior.In group A,20 patients(51.74%)had fluorescence leakage in macular arch region at late stage,while none of the patients in group B had fluorescence leakage in the same region.2.Analysis of visual field results in monocular disease groupIn group A,42.86% of the visual field showed arcuate defect connected with the physiological blind spot,The results of visual field in group B showed that 54.55%;30 patients(85.71%)in Group A and 10 patients(90.9%)in Group B had the highest percentage of defects in the inferior.3.Analysis of OCTA vascular parameters in the affected eye and the unaffected eye of the monocular disease group The analysis of OCTA results in group A and group B showed that the peripapillary capillary density in the affected eye was lower than that in the unaffected eye(P<0.05 for both).In group A,the total capillary density in the affected eyes was lower than that in the unaffected eyes(P<0.05),and the area of large blood vessels around the optic disc in the affected eyes was higher than that in the unaffected eyes(P<0.05);4.Analysis of correlation between OCTA vascular parameters and visual field in patients with monocular diseaseIn group A,there was no correlation between the capillary density in the optic disc,the peripapillary capillary density,the capillary density of the whole optic disc and MD or PSD values(P>0.05 foe all);There was a positive correlation between the peripapillary capillary density and MD value in group B(r=0.764,P=0.006);There was no correlation between the peripapillary capillary density and visual field PSD in group B,and there was no correlation between peripapillary capillary density,total optic disc capillary density and MD or PSD(P>0.05 for all).5.Analysis of the consistency between FFA and OCTA in patients with monocular diseaseThe imaging findings of FFA and OCTA in group A showed a good diagnosis consistency of ischemic region in superior(K=0.751)、inferior(K=0.606)、 nasal(K=0.557)、temporal(K=0.565)were good(P<0.05 for all),and the superior diagnosis consistency was excellent;The imaging of FFA and OCTA in group B showed that the diagnosis of ischemic area in the superior(K=0.744)and nasal(K=0.560)directions wer consistent,while the diagnosis consistenc in the inferior(K=0.233)and temporal(K=0.298)directions were poor.6.Analysis of the consistency between FFA and visual field in the patients with monocular diseaseThere are 65.71% patients whose FFA ischemic area corresponded to the visual field defect area in Group A.There are 72.72% patients whose FFA ischemic area corresponded to the visual field defect area in Group B.7.Analysis of FFA,visual field and OCTA results in patients with bilateral diseasesFFA results showed sustained low fluorescence in the optic disc in 4 of the 5patients(10 eyes)in Group C(all of them were the initial affected eyes).The most common visual field result(3 eyes)is an arcuate defect connected to the physiological blind spot.In OCTA image analysis,the area of large vessels around the optic disc,the ratio of peripapillary capillary density,the ratio of capillary density in the optic disc,and the mean ratio of capillary density in the whole optic disc of the initial affected eye were smaller than those of the post-onset eye,and the area of large vessels in the optic disc of the initial affected eye was larger than that of the later one.In 2 eyes’ optic disc with persistent low fluorescence in FFA,centripetal visual field narrowing occurred;FFA and OCTA images showed consistent ischemic areas in 7eyes.Conclusions:OCTA is capable of noninvasive,high-speed,and quantitative assessing the optic disc blood flow in patients with NAION.This study shows that it is easier to identify ischemic regions by analyzing the blood flow in the peripapillary capillary density,regardless of the acute or chronic phase.In the diagnosis of NAION patients,OCTA’s judgment of ischemic regions is consistent with FFA results,but the correlation between capillary density parameters and MD or PSD of the visual field is not significant.In the future,OCTA can replace part of FFA tests,but it cannot completely replace visual field tests.Our FFA findings suggest that there may be retinal vein dysfunction on the ipsilateral side of the ischemic optic disc in NAION patients,the specific mechanism still needs further research with a larger sample size. |
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