To report a case of Intraoperative Floppy Iris Syndrome (IFIS) experienced during pars plana vitrectomy and phacoemulsification in a patient using tamsulosin, which is a selective alpha 1 adrenergic antagonist.

A 77-year-old male who had used tamsulosin for the previous month for prostate cancer visited our clinic with left visual disturbance, that had developed a week earlier. The best-corrected visual acuity of the left eye was 0.02 and both pupils showed incomplete mydriasis. Pars plana vitrectomy and phacoemulsification with PCL implantation were performed on his left eye to correct a left cataract and retinal vein occlusion with vitreous hemorrhage. Phacoemulsification idenfied a billowing iris and progressive pupillary constriction. Therefore, we administered an intracameral epinephrine injection and applied an iris hook. The procedure was completed successfully without any complications. The best-corrected visual acuity of the left eye was good as at 0.9, and iris depigmentation and atrophy were checked two months postoperatively in the right eye, which had not had any previous surgical history.

A detailed medical history taking is essential because IFIS may raise the risk of intraoperative complications, such as posterior capsule rupture, especially when the small pupil is small. Safe procedures must be planned with cessation of tamsulosin at least a week preoperatively.