Bilateral acute iris transillumination (BAIT) syndrome: Differential diagnosis based on clinical, OCT and UBM findings

Introduction Bilateral acute iris transillumination (BAIT) is a relatively new syndrome whose etiopathogenesis is still not fully understood. It is characterized by acute bilateral onset of intense pigment dispersion in the anterior chamber, iris depigmentation with severe transillumination defects, accentuated pigment deposition in the angle, and elevated intraocular pressure (IOP). In literature, the first case was of bilateral acute iris depigmentation (BADI) reported in 2004 in a 77-year-old woman. In 2019, Perone et al. published a review about BAIT syndrome. They reported a total of 79 cases have been published up that date, mainly in Europe and especially in Turkey and Belgium. The majority of reported cases were of bilateral acute iris depigmentation (BADI). BAIT syndrome might be mainly confused with acute iridocyclitis, acute primary angle-closure (APAC) and pigment dispersion syndrome (PDS). In relation to BAIT, controversies still exist regarding the etiology being the differential diagnosis of paramount importance for adequate treatment. Purpose To report a case of BAIT syndrome associated to refractory glaucoma and to discuss the differential diagnosis based on clinical, OCT and UBM findings. Methods We present a case of BAIT syndrome in which clinical, OCT and UBM findings have pointed out the similarities and, mainly the diagnosis differences with other ocular diseases. Conclusions BAIT syndrome with accentuated IOP rise must be differentiated of other ocular diseases. It requires urgent clinical therapy and/or surgical management as occurred in the present case for avoiding structural damage in OCT and visual field loss. OCT and UBM are critical for early recognition, differential diagnosis and management.