Atypical Bilateral Iris Transillumination without Pigment Dispersion: A Case Report Suggestive of BAIT

Bilateral Acute Iris Transillumination (BAIT) is a rare ocular condition characterized by acute iris depigmentation, pigment dispersion in the anterior chamber, sphincter paralysis, and frequently elevated intraocular pressure. However, atypical presentations may occur, complicating diagnosis and expanding the clinical spectrum of the disease.

A 25-year-old woman presented with acute onset of severe photophobia associated with migraine and visual aura. Slit-lamp examination revealed bilateral diffuse 360° iris transillumination and nearly fixed atonic mydriasis, in the absence of pigment dispersion, anterior chamber inflammation, or intraocular pressure elevation. Systemic evaluation revealed recent respiratory illness and associated dermatologic manifestations. No ocular treatment was initiated due to the absence of inflammatory signs or ocular hypertension. Photophobia resolved spontaneously, while iris abnormalities persisted.

This case suggests a possible pigment-negative or incomplete variant of BAIT, characterized by the absence of pigment dispersion and normal intraocular pressure. Recognition of such atypical presentations is essential to avoid misdiagnosis and unnecessary treatment, and may contribute to a broader understanding of the clinical spectrum and pathophysiology of BAIT.