Multimodal imaging (MMI) has transitioned from a supportive role to a central pillar in the early diagnosis of Vogt-Koyanagi-Harada (VKH) disease because it can detect subclinical inflammation that is often invisible during a conventional clinical examination. By integrating various technologies, clinicians can visualize dynamic inflammatory changes with anatomical specificity, allowing for early aggressive treatment that can alter the disease trajectory.

The role of specific imaging modalities in early diagnosis includes:

• Indocyanine Green Angiography (ICGA): Regarded as the gold standard for assessing the choroid, ICGA provides a direct window into the choroidal stroma where VKH originates. It is uniquely capable of detecting subclinical choroiditis during the prodromal phase—even when standard retinal imaging appears normal—by revealing early choroidal vasculitis and granulomatous infiltration. Hallmark early signs include hypofluorescent dark dots (HDDs), which represent active stromal inflammation and are often invisible on other modalities.
• Optical Coherence Tomography (OCT) and EDI-OCT: OCT provides a non-invasive, high-resolution view of structural changes. Enhanced depth imaging (EDI-OCT) is particularly critical for quantifying choroidal thickening, which is one of the most important indicators for distinguishing VKH from other uveitic diseases. In very early stages, OCT can detect minor retinal detachment that may be missed by clinical inspection or fluorescein angiography. Other early biomarkers include Bacillary Layer Detachment (BLD), which signifies intense exudative activity, and RPE undulations, which reflect mechanical pressure from the underlying inflamed choroid.
• Fundus Fluorescein Angiography (FFA): This modality is essential for identifying the breakdown of the blood-retinal barrier. A “signature” finding of early-stage VKH on FFA is the presence of multiple hyperfluorescent pinpoints (leakage at the RPE level) and subsequent subretinal dye pooling.
• Ultrasound Biomicroscopy (UBM): Because VKH often begins as a stromal choroiditis that can involve the ciliary body, UBM provides a non-invasive window into early anterior segment inflammation. It can uniquely visualize ciliary body thickening or detachment and the forward rotation of ciliary processes, which may elude conventional slit-lamp examinations.
• B-scan Ultrasonography: This tool is particularly valuable in the early inflammatory phase to document diffuse choroidal thickening and serous retinal detachment, especially in patients where media opacities (like cataracts or corneal edema) prevent optical imaging.

By using these tools in a stage-specific framework, clinicians can achieve early recognition and prompt intervention, which is the key therapeutic goal to prevent irreversible fundus damage and complications. This approach supports an emerging “zero tolerance to choroiditis” paradigm, triggering treatment at the first sign of choroidal involvement regardless of clinical symptoms.

Xia, Lan, et al. “Vogt-Koyanagi-Harada Disease Under the Lens: Insights from Multimodal Ocular Imaging.” Prog. Retin. Eye Res., vol. 101445., 4 Feb. 2026, doi:10.1016/j.preteyeres.2026.101445.