Which class is associated with floppy iris syndrome during cataract surgery?

• A. Beta blockers
• B. Alpha blockers
• C. Alpha agonists
• D. PDE inhibitors

Answer: (B)

Floppy iris syndrome during cataract surgery happens because alpha-adrenergic blockade reduces the tone of the iris dilator muscle. Medications that block alpha-1 receptors, especially selective alpha-1 blockers used for benign prostatic hyperplasia such as tamsulosin, can leave the iris less tense. In the operating room, this loss of support allows the iris to billow, billow, and constrict unpredictably as fluid is irrigated, making the pupil unstable and increasing the risk of iris prolapse or poor visualization. That’s why alpha-blockers are the class most closely associated with this phenomenon.

Beta blockers don’t have a major effect on the iris dilator muscle, so they don’t typically cause floppy iris syndrome. Alpha agonists would promote dilation rather than floppy iris behavior, and PDE inhibitors don’t have the same link to iris muscle tone changes.