Situation: A 72-year-old man with type 2 diabetes mellitus and hypertension is scheduled for phacoemulsification with intraocular lens implantation in the right eye under topical anesthesia. Over the past 2 years he has noticed gradually blurred vision and glare when driving at night. During the preoperative interview, which of his medications should the nurse specifically bring to the eye surgeon's attention because it affects the operation itself?

Alpha-1 adrenergic blockers such as tamsulosin cause intraoperative floppy iris syndrome: the iris billows and the pupil constricts during phacoemulsification, raising the risk of complications. The surgeon needs to know so that technique and drugs can be adjusted.

Why tamsulosin matters before cataract surgery

The key issue here is not whether the patient’s chronic conditions are controlled, but whether any current drug changes the surgical conditions inside the eye during phacoemulsification. Tamsulosin is an alpha-1 adrenergic receptor antagonist used for benign prostatic hyperplasia. Its blockade of alpha-1 receptors in the iris dilator muscle is the central concern.

During cataract surgery, the pupil must remain dilated so the surgeon can see and remove the lens. In patients taking tamsulosin, the iris may behave abnormally: it billows or flutters with normal intraocular fluid currents, prolapses toward the surgical incisions, and undergoes progressive miosis even after pharmacologic dilation. This triad is called intraoperative floppy iris syndrome (IFIS) ^[1][3].

The mechanism is not fully settled. Early thinking attributed IFIS to sympathetic blockade of the iris dilator, but IFIS can occur even after the drug is stopped, suggesting structural or receptor-level changes that persist ^[1]. A meta-analysis of 17,588 eyes confirmed that current tamsulosin use is a strong, independent risk factor for IFIS, while hypertension and diabetes alone were not consistently predictive ^[2]. This is important for this patient: he has both hypertension and type 2 diabetes, but those conditions do not explain the specific intraoperative risk the way tamsulosin does.

Watch out! IFIS is not an allergy or a drug interaction in the usual sense. The danger is mechanical and intraoperative: a floppy iris can obstruct the capsulorhexis, get aspirated into the phaco tip, or lead to iris trauma, posterior capsule rupture, and vitreous loss ^[3][4].

The other medications do not require the same level of surgeon alert for the operation itself. Atorvastatin, metformin, and amlodipine affect systemic cardiovascular or metabolic status, but they do not alter iris behavior during phacoemulsification. They are relevant to preoperative clearance and perioperative monitoring, not to the surgical technique.

Key point! The nurse’s role is to specifically identify tamsulosin and communicate it to the surgeon before the procedure, because the surgeon may need to adjust technique or use intracameral agents to manage IFIS. A real-world pharmacovigilance study also supports that drug-associated IFIS is linked to higher rates of severe intraoperative complications, reinforcing the need for preoperative risk stratification ^[4].

The correct answer is therefore tamsulosin 0.4 mg once daily, because it directly affects the operation itself through IFIS, independent of the patient’s diabetes or hypertension.