Changes in ocular blood flow and retinal oxygen metabolism during immunosuppressive therapy for initial-onset acute uveitis associated with Vogt-Koyanagi-Harada disease.

Abstract

Purpose The aim of this study was to investigate the correlations between visual acuity, blood flow velocity in the choroid and optic nerve head (ONH) and oxygen saturation and calibre of retinal vessels during immunosuppressive therapy in patients with initial-onset acute uveitis associated with Vogt–Koyanagi–Harada (VKH) disease. Methods In this prospective study, 20 patients were studied. Laser speckle flowgraphy (LSFG) and retinal oximetry measurements were performed at baseline and at 4, 8 and 12 weeks after treatment. Results After immunosuppressive therapy, best-corrected visual acuity (BCVA) improved significantly at each post-treatment time-point compared with baseline value. Mean blur rate (MBR), representing blood flow velocity, in the choroid and ONH (overall and vessel areas) significantly increased. On the contrary, oxygen saturation of retinal arterioles and venules and calibre of retinal venules significantly decreased. There were significant negative correlations between ONH MBR vessel and arteriovenous oxygen saturation difference at baseline and at 4 weeks after treatment and between MBR tissue of the ONH and arteriovenous oxygen saturation difference at week 12 after treatment. Conclusions Immunosuppressive therapy in patients with initial-onset acute uveitis associated with VKH disease is associated with improved blood flow velocity in choroid and ONH and normalization of retinal oxygen metabolism and calibre of retinal venules. These correspond with improved visual acuity. These findings help explain the pathophysiology of VKH disease and its treatment and may provide biomarkers for choroiditis activity and response to treatment.