In Vogt-Koyanagi-Harada (VKH) syndrome, the characteristic choroidal thickening seen on enhanced depth imaging OCT (EDI-OCT) is most prominent during which phase?

• A Convalescent phase with development of 'sunset glow fundus'
• B Acute uveitic phase with exudative retinal detachments and disc hyperemia ✓
• C Prodromal (meningitic) phase before ocular symptoms develop
• D Chronic recurrent phase with peripheral depigmentation

Explanation

VKH disease progresses through four phases: prodromal (meningitic), acute uveitic (ocular), convalescent, and chronic recurrent. The acute uveitic phase is characterized by bilateral anterior uveitis, exudative retinal detachments (due to choroidal inflammation and disruption of the outer blood-retinal barrier), optic disc hyperemia, and serous detachments. On EDI-OCT, choroidal thickening is greatest during the acute uveitic phase, reflecting maximum choroidal inflammation, stromal expansion from edema, and dilated choroidal vessels. As the disease responds to systemic corticosteroids and transitions to the convalescent phase, choroidal thickness normalizes and sunset glow fundus (diffuse choroidal depigmentation) develops due to melanocyte destruction.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

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Written and medically reviewed by the StethoPrep medical team.