BACKGROUND: Detection of choroidal inflammation in Vogt-Koyanagi-Harada (VKH) disease is still a challenge. Progression to sunset glow fundus has been observed despite apparent good clinical control of inflammation. Indocyanine green angiography (ICGA) permits choroid inflammation detection, though it is invasive, time consuming, and costly. The purpose of the present study is to report a sign indicative of probable inflammation on enhanced depth imaging spectral-domain optical coherence tomography (EDI-OCT): a localized increase in choroidal thickness with bulging of the outer retina ('choroidal bulging') in patients with VKH disease in the non-acute uveitic stage. FINDINGS: This is a retrospective observational study. The choroidal bulging was a particular finding observed in four eyes of three patients with VKH disease in the non-acute uveitic stage (median disease duration 55.3 ± 40.3 months, range 10 to 108). This study is part of an ongoing longitudinal study in patients with VKH disease carried out in the Uveitis Service, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil. In all eyes, the choroidal bulging was identified in the presence of anterior chamber cells and/or on fundus angiographic (fluorescein and indocyanine green) findings, indicative of disease activity. Changes in the thickness of the choroidal bulging accompanied the variation in the clinical and angiographic signs of inflammation. CONCLUSION: The choroidal bulging is a particular finding detected on EDI-OCT that may indicate ongoing inflammation in the posterior segment of the eye. This EDI-OCT feature may assist in the treatment-monitoring of patients with Vogt-Koyanagi-Harada disease in the non-acute uveitic stage.