Multi-Spectral Image Analysis In Vogt–Koyanagi–Harada Disease

Background: Vogt-Koyanagi-Harada(VKH)syndrome is an autoimmune disorder attacking against pigmented cells,resulting in blindness and affecting multiple organs including eyes,ears,meninges,hair and skin.In the acute uveitic stage,typical features of VKH disease include a generalized choroiditis with exudative retinal detachment.In the convalescent(chronic)stage,it is often accompanied by a bright orange-red fundus also called “sunset glow fundus”.Accessory examinations including fundus fluorescein angiography(FFA),optical coherent tomography(OCT),Indocyanine green angiography(ICGA)and fundus photography(FP)are helpful to evaluate the ocular changes in VKH disease.The application of multi-spectral imaging(MSI)in VKH disease has not yet been reported and was therefore the subject of the study presented here.Purposes: To investigate fundus abnormalities in Vogt–Koyanagi–Harada(VKH)syndrome by a non-invasive tool,multi-spectral imaging(MSI).Methods: A total of 77 VKH patients and 163 healthy controls were enrolled.All patients underwent multi-spectral imaging(MSI),fundus fluorescein angiography(FFA),optical coherent tomography(OCT)and fundus photography(FP).MSI was also performed in healthy controls.Based on VKH patients’ disease duration(<2 weeks,2 weeks ~ 2 months,>2 months)and stage of active or inactive,we concluded the characters of MSI in patients.The MSI findings were evaluated in combination with FFA,OCT and FP.Additionally,we compared extent of exposure of choroidal blood vessels between VKH patients and health control under a same wavelength(590nm)to evaluate retinal transmission function of them.Results: A number of features could be recognized by MSI which included a)general depigmentation,b)clumping of pigment and c)macular depigmentation and/or hyperpigmentation.d)an extensive fine grainy depigmentation mottled with hyperpigmentation.The percentages of these former three abnormalities discovered by MSI in 52 inactive VKH patients with a duration of more than 2 months in VKH were 67.3%,75% and 84.6% respectively,which were all significantly higher than those detected by FFA,OCT or FP(p=0.0398~p<0.0001).A fourth feature,which is characterized by an extensive fine grainy depigmentation mottled with hyperpigmentation was only detected by MSI in VKH patients.Additionally,our study showed that MSI detected higher percentages of these four abnormalities in patients with sunset glow fundus than in patients without this phenomenon(p=0.0492 ~ p<0.0001).At same wavelengths(590nm),exposure of choroidal blood vessels in inactive patients was stronger than in health controls and active patients(p=0.00,p=0.000).Conclusions: Our results show that MSI is a sensitive non-invasive method to investigate the retinal pigment epithelium(RPE)in VKH disease.It is more likely to detect RPE abnormalities with MSI than when using FFA,OCT or FP.Retinal transmission function in inactive patients are stronger than that in active patients and health control.