<p>A 22-year-old female patient was referred for glaucoma evaluation due to an unclear bilateral ocular condition. For 6 months she had experienced glare sensitivity and dilated pupils without visual impairment. Initially, bilateral anterior uveitis with elevated intraocular pressure (IOP) had been diagnosed and treated locally with topical steroids and latanoprost. Clinical examination revealed bilateral diffuse iris transillumination defects with irregular, nonreactive mydriasis as well as heavily pigmented anterior chamber angles. Extended medical history revealed pneumonia treated with systemic moxifloxacin 2 weeks prior to symptom onset. Based on this correlation, the diagnosis of bilateral acute iris transillumination syndrome (BAIT) was established, which is a rare and likely underdiagnosed syndrome that is frequently mistaken for uveitis or pigment dispersion syndrome. Although the pathogenesis has not yet been fully clarified, associations with moxifloxacin therapy and respiratory tract infections have been described. Middle-aged women are predominantly affected. Clinically, the acute phase is characterized by conjunctival hyperemia combined with loss of the iris pigment epithelium, resulting in acute pigment dispersion into the anterior chamber. Subsequently, irreversible diffuse iris transillumination defects and enlarged atonic pupils develop. Pigment deposition within the anterior chamber angle can lead to ocular hypertension and rarely a secondary glaucoma. Careful history taking, regular IOP monitoring and symptomatic treatment of photophobia are essential. Awareness of this syndrome prevents unnecessary, time-consuming and costly uveitis work-up.</p>