| Purpose:To describe optical coherence tomography angiography(OCTA)features of Vogt-Koyanagi-Harada disease(VKH)patients at various disease stages and to explore the potential clinical values of quantitative OCTA measurements in diagnosis,follow up,and outcome prediction in VKH patients.Contents:OCTA scans and reconstructions obtained from VKH patients were analyzed and changes in retinal/choroidal structure,light reflectivity and vasculature morphology were described.Foveal avascular zone(FAZ)area,vascular densities of the capillary layers,foveal retinal thickness(FRT)and subfoveal choroidal thickness(SFCT)were measured and compared between VKH patients at acute,chronic quiescent and chronic anterior uveitis recurrent stages,and normal control.These OCTA measurements were analyzed with the clinical data to evaluate their clinical significances.Patients and methods:This is a retrospective study.VKH patients who underwent OCTA scans between April 2015 and May 2018 in Peking Union Medical College Hospital were included.Medical records of the patients were reviewed carefully and results of ophthalmological examinations including best corrected visual acuity(BCVA),slit-lamp evaluations of the anterior segment,and direct and/or indirect fundoscopy were documented.Patients were grouped into acute uveitic,chronic quiescent and chronic anterior uveitis recurrent stages in terms of disease duration and clinical findings.OCTA scans were obtained by AngioVue(Optovue,Fremont,CA,USA)and analyzed by built-in software version 1.0 and 2.0.Qualitative descriptions obtained include image quality grades,accuracy of the automatic stratification,with or without retinal detachment,choriocapillary flow voids,deep capillary plexus(DCP)concentric folds and choroidal neovascularization(CNV);quantitative measurements include FAZ area,superficial capillary plexus(SCP),DCP,choroidal capillary(CC)vascular density,FRT and SFCT.Statistical analysis was processed with IBM SPSS Statistics for windows,Version 22.0(Armonk,NY,IBM Corp.).Results:One hundred and ten VKH patients(219 eyes)averaged 41.8 years old were included.Eight hundred and twenty-nine OCTA images were obtained,of which 750(90.47%)were graded automatically as a quality of Q5 or above;53(105 eyes),92(181 eyes)and 26 patients(47 eyes)had OCTA scans at acute,chronic quiescent and chronic anterior uveitis recurrent stages,respectively.As compared with traditional OCT techniques,OCTA revealed novel features including choroidal hypoperfusion areas,flow voids(4.11%)and DCP concentric folds(1.37%),and was able to clearly visualize the vasculature of secondary CNVs(3.65%).As for the quantitative measurements,FAZ,SCP,DCP and CC vascular densities were 0.33±0.12mm2,46.79%±4.58%,48.40%±4.78%and 66.11%±2.21%respectively in VKH patients,and were 0.31±0.09 mm2,48.33%±2.85%,53.19%±2.91%and 66.89%± 1.28%respectively in normal control;FRT and SFCT were 254.63±95.73 and 357.89±168.1?m respectively in VKH patients,and were 254.63?95.73 and 357.89 ± 168.1?m in normal control.All the above measurements except FAZ area were significantly lower than those observed in age matched normal control.Anyalisis of the 45 patients who underwent OCTA scan in at least two different disease stages revealed that anterior uveitis recurrence during follow up had significantly lower vascular densities(differences in SCP,DCP and CC vascular densities were-3.02%±0.34%,-2.84%±0.41%and-1.37%±0.17%,respectively;P=0.000)and significantly thicker choroid(difference in SFCT was 32.62±11.45?m,p=0.005)than those without.Notably,either when all of the patients were included or when the 45 patients with OCTA data spanning at least two disease stages were included,DCP vascular densities were found to be negatively correlated with logMAR BCVA in all 3 disease stages with r values ranged from-0.184 to-0.647,and p values ranged from 0.000 to 0.036).However,in the 20 patients who underwent OCTA scans at both chronic quiescent and chronic anterior uveitis recurrent stages,none of the measurements were found to be associated with anterior uveitis recurrence.Conclusion:OCTA features of VKH include choroidal hypoperfusion areas,choriocapillary flow voids and DCP concentric folds.The morphology and dynamic changes of secondary CNV can be observed and followed up with OCTA.Marked decrease of vascular densities in all retinal and choroidal capillary layers were observed in acute,chronic quiescent and chronic recurrent stages of VKH,suggesting that defective retinal and choroidal microcirculation might be a pathogenetic hallmark in VKH,which might be associated with low visual outcome and disease recurrence.DCP vascular density,in particular,might be a useful parameter for disease monitoring and predictor of visual outcome in all disease stages. |
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