Patients on drugs to treat prostate enlargement should inform their eye surgeon about the medications before eye surgery, several U.S. groups advise.

The American Society of Cataract and Refractive Surgery, the American Academy of Ophthalmology and the American Urological Association say that alpha-blockers such as Flomax and other similar systemic drugs can potentially cause difficulty during cataract surgery, particularly if the eye surgeon has not been forewarned.

The alpha-blocker drugs are all regarded as being safe and effective for the treatment of urinary symptoms due to prostate enlargement without harming the eyes; however, Drs. David F. Chang and John R. Campbell completed both a retrospective and a prospective study of 1,600 patients that found the medications can impair the dilator muscle in the iris.

“Flomax does not affect vision or eye health,” Chang said. “But it impairs the dilator muscle in the iris, and during cataract surgery the pupil needs to stay dilated.”

If the surgeon knows in advance that the patient is or has taken an alpha-blocker drug, then appropriate techniques can be used that provide excellent results, according to Chang.