The Noninvasive Indicators For Ischemia In Retinal Vein Occlusion And Characteristic Of Macular Edema On Fundus Autofluorescence

Purpose:The aim of this study was to investigate the characteristics of macular edema observed by fundus autofluorescence(FAF)and to analyze noninvasive indicators of ischemia in RVO through FAF or spectral domain optical coherence tomography(SD-OCT).Method:Thirty eyes of 30 patients with RVO and 15 healthy control eyes were included in the study.RVO patients were divided into non-ischemic and ischemic RVO groups.All patients were given a complete ophthalmologic examination and dominant eye test and were evaluated using FAF,fundus fluorescein angiography(FFA),and SD-OCT.The optical intensities of the inner and outer retinal layers were measured using ImageJ software.Choroidal thickness was assessed using enhanced depth imaging-OCT(EDI-OCT)imaging through SD-OCT,and SPSS 23.0 software was used for statistical analysis.Results:Of our 30 patients,14(46.67%)were male,and 16(53.33%)were female;14 eyes(46.67%)presented with non-ischemic RVO and 16 eyes(53.33%)presented with ischemic RVO.The dominant eyes were affected in 7 patients.FAF imaging showed typical macular cystoid edema with high autofluorescence in 10 of the 14 non-ischemic RVO patients(71.43%)and in 4 of the ischemic RVO patients(25%).Disorganization of retinal inner layers(DRIL)was observed in 7 eyes(50%)in the non-ischemic RVO group and 14 eyes(87.5%)in the ischemic RVO group.The prominent middle-limiting membrane p-MLM sign was found in 3 eyes(21.43%)in the non-ischemic RVO group and 9 eyes(56.25%)in the ischemic RVO group.The mean central foveal thickness(CFTs)in the non-ischemic(480.57±235.514 μm)and ischemic(403.69±179.329 μm)RVO groups were significantly higher than that in the control group(224.53±16.977 μm,p<0.01).There was no significant difference in subfoveal choroidal thickness(SFCT)between either of the groups.The mean optical intensity of the outer retinal layer in the ischemic group(109.78 ±19.327)was significantly lower compared to the non-ischemic RVO group(172.31 ±30.527)and the control group(184.70±18.462).Conclusions:1.In patients with macular edema observed on OCT but not FAF,RVO was considered ischemic.2.We conclude that the presence of DRIL,p-MLM sign,integrity of the external limiting membrane(ELM),and decreased optical intensity or integrity of the ellipsoid zone and retinal pigment epithelium(RPE)can be used as effective indicators to estimate ischemia in RVO patients.3.Branch Retinal vein occlusion(BRVO)was the most common type of ischemic RVO.