Decrease of choriocapillary vascular density measured by optical coherence tomography angiography in Vogt-Koyanagi-Harada disease.

Purpose: Changes of choroidal circulation throughout the disease course of Vogt-Koyanagi-Harada (VKH) disease and the clinical significance remain unclear. Choriocapillary vascular density (CC VD) measured by optical coherence tomography angiography (OCTA) were compared in different disease stages of VKH and its correlation with other parameters was analyzed, aiming to explore their clinical relevance.

Methods: This is a retrospective case series. One hundred and fourteen VKH patients and 47 normal controls (NCs) were included. Patients were grouped into the acute uveitic, convalescent, and chronic recurrent stages (only anterior recurrent cases included), and OCTA images were obtained from VKH patients in these stages. Best corrected visual acuity (BCVA), CC VD, and subfoveal choroidal thickness (SFCT) were recorded and compared.

Results: CC VD in acute (58.26% ± 0.84%), convalescent (64.85% ± 0.33%), and chronic recurrent (62.78% ± 0.70%) stage of VKH patients were all significantly lower than that in NCs (66.37% ± 0.41%) (p < 0.001, p = 0.017, and p < 0.001, respectively). CC VD increased by 6.59% ± 0.91% with resolution of acute inflammation (p < 0.001) and decreased by 2.07% ± 0.74% during anterior uveitis relapse (p = 0.009). Patients with a positive history of anterior recurrence had lower CC VD (- 2.43% ± 0.75%, p = 0.003) in the convalescent stage than those without. CC VD was negatively correlated with logMAR BCVA in VKH (r =  - 0.261, p < 0.001).

Conclusion: CC VD was decreased in every stage of VKH. CC VD has the potential to reflect the status of uveitis and might be promising in monitoring the disease activity. OCTA is a convenient and straightforward tool to evaluate choroidal vascularity, and CC VD provides supplemental quantitative information of the choriocapillaris. Further studies are needed to explore the values of OCTA quantitative parameters in monitoring VKH progression, predicting visual prognosis, and guiding clinical decisions.