Intraoperative floppy iris syndrome: pathophysiology, prevention, and treatment.

Purpose: To extend upon previous reports, observations, and discussions of intraoperative floppy iris syndrome (IFIS) with the goal of providing new insight into the syndrome's pathophysiology, prevention, and treatment.

Methods: Following a review of IFIS and its relationship to autonomic pharmacology, evidence for anatomic changes following exposure of humans and other animals to autonomic drugs is described. The clinical implications for these findings are discussed as they relate to the treatment and prevention of this syndrome.

Results: IFIS has been associated with the use of adrenergic antagonists even after they have been discontinued years prior to surgery. Some investigators believe that this persistence of IFIS reflects anatomic structural change. Evidence from laboratory experiments and human clinical studies using topically applied and systemic autonomic drugs supports the possibility of anatomic changes coexisting with IFIS observed during cataract surgery.

Conclusions: IFIS is a relatively rare syndrome, often associated with the use of systemic alpha-blockers and conditions that influence dilator muscle tone. Laboratory and clinical evidence supports the possibility of anatomic changes following the use of autonomic drugs. The persistence of IFIS years after cessation of treatment with alpha-blockers suggests that the potential risks of discontinuing these drugs prior to cataract surgery outweigh potential benefits.