Pathophysiology and Pre-Operative Evaluation of Patients at Risk for Intraoperative Floppy Iris Syndrome (IFIS)

Intraoperative Floppy Iris Syndrome (IFIS) has received a significant amount of attention and subsequent research since it was first reported in 2005 (Bell et al., 2009; Blouin et al., 2007; Chang & Campbell, 2005; Chang et al., 2007; Oshika et al., 2007; Srinivasan et al., 2007; Takmaz & Can, 2007). Current and former uses of alpha-1 adrenergic receptor (α1AR) antagonists—most notably tamsulosin—appear to be at the highest risk for this surgical complication (Chang & Campbell, 2005). IFIS is characterized by loss of muscle tone in the iris, thereby preventing mydriasis and involves a triad of pupil constriction, fluttering and billowing of the iris stroma, and propensity for iris prolapse during cataract surgery (Chang & Campbell, 2005). While α1AR antagonists are often used for various urological conditions, they also block α1AR receptors in the iris dilator muscle and may worsen muscle tone and lead to the iris billowing sometimes seen in cataract surgery. Without adequate pupil dilation, IFIS reduces visualization of the surgical field, including the cataract itself. This impairs removal and can lead to other complications including rupture of the posterior capsule, which further increases the risk of other vision-threatening complications of cataract surgery (Schwinn & Afshari, 2006).