OCTA Features In The Early Stage And Treatment Strategy For Advanced Stage Of Familial Exudative Vitreoretinopathy

ObjectiveThis study aims to examine the early retinal changes in the posterior pole in patients with Familial exudative vitreoretinopathy(FEVR)in OCTA,explore the pathogenesis of FEVR,look for meaningful and sensitive Imaging biomaker,and evaluate its applicable value as a screening indicator for early stage of FEVR,which may provide convenience,fast and non-invasive testing methods for early diagnosis of FEVR.Meanwhile,to investigate the clinical characteristics of FEVR-related retinal detachment(RD)patients,evaluate visual prognosis,and identify the best strategy for the treatment of RD in FEVR.Methods1.The characteristics of OCTA in early FEVR patients: 31 patients with FEVR and31 controls were included for a cross-section observational study.Using OCTA to measure(1)macular structure and blood flow parameters of early FEVR patients:full retinal thickness,inner retinal thickness,outer retinal thickness,total foveal volume,inner foveal volume,outer foveal volume,total parafoveal volume,inner parafoveal volume,outer parafoveal volume,foveal avascular zone(FAZ)area,FAZ perimeter,FD-300,superficial vessel density and deep vessel density.(2)optic disc structure and blood flow parameters: the thickness of the nerve fiver layer around the optic disc and the blood flow density of the radial peripapillary capillary(RPC).2.Treatment study of patients with advanced FEVR: a retrospective study was conducted of patients who were diagnosed with FEVR-related RD.Twenty-eight eyes of 24 patients were included for study.And the latest stage system of FEVR(2014)was used to stage FEVR patients.All cases had preoperative and postoperative clinical evaluations,demarcation laser treatment and scleral buckling(SB),pars plana vitrectomy(PPV)or combined techniques were performed to reattach the retina.Pearson correlation and Spearman correlation were used to analyze the results.Results1.The parafoveal full retinal thickness,parafoveal inner retinal thickness,parafoveal outer retinal thickness,total parafoveal volume,inner parafoveal volume,parafoveal superficial vessel density and parafoveal deep vessel density were lower in the FEVR group than in the control group(p<0.05).2.The FAZ area,FAZ perimeter,FD-300 were lower in the FEVR group than in the control group(p<0.05).The IRT was negatively correlated with FAZ area(r=-0.746,p<0.05).3.The thickness of RNFL in the temporal inferior,temporal superior,superior temporal retinal areas was lower in the FEVR group than in the control group(p<0.05).4.The all RPC density in the whole-image,inside disc,peripapillary,superior-hemi were lower in the FEVR group than in the controls(p<0.05).The small vessels RPC density was lower in the superior-hemi and nasal superior retinal area in the FEVR group than in the control group(p<0.05).5.In the FEVR with RD study,the male to female ratio was 13:11,the average age was 22.96 ± 9.98 years,as for the refractive status,most patients are myopic.Four out of 24 patients developed RD in both eyes,and all of them were RRD.Of all the studied eyes,25 eyes were RRD and 3 eyes were TRD.No giant tears were found in all cases,1 case of macular hole(4.00%),2 cases of horseshoe-shaped tear(8.00%),and the remaining 22 cases with holes(88.00%).Most of the holes were in the temporal half of the retina.6.Two of our studied eyes were in stage 3A,3 in stage 3B,3 in stage 4A,18 in stage4 B,and 2 in stage 5A.Both the 3A eyes were treated with demarcation laser photocoagulation,and both the 5A eyes underwent vitrectomy combined scleral bulking.The rest of the patients chose different treatment options according to other ocular anomalies.The patients postoperative BCVA were positively correlated with preoperative visual acuity,number of operations,range of retinal detachment,macular drag and the severity of proliferative vitreoretinopathy.Conclusions1.There may be microstructural changes and microvascular defects in the macular and optic disc in early FEVR patients.The parafoveal full retinal thickness,parafoveal inner retinal thickness,parafoveal outer retinal thickness,total parafoveal volume,parafoveal superficial vessel density and parafoveal deep vessel density are reduced,the FAZ area,the FAZ perimeter and the FD-300 are decreased,parafoveal SVD and parafoveal DVD are also decreased.These may be the potential Imaging biomakers of early FEVR.OCTA can be used for noninvasive screening for early FEVR.2.RRD is more common than TRD in patients with FEVR related RD.The hole is mostly located in the temporal half.The latest FEVR staging system has certain guiding significance in the treatment of FEVR patients with RD.Useful vision may be obtained by proper treatment FEVR eyes with RD.