In 2005, John Campbell and I first described a new small pupil syndrome that we named intraoperative floppy iris syndrome (IFIS) (J Cataract Refract Surg. 2005;31:664-673). Classic IFIS manifests as a triad of intraoperative signs beyond poor pupil dilation: iris billowing and floppiness; iris prolapse to the main and side incisions; and progressive miosis (Figure 1). Particularly if such iris behavior is unexpected, the rate of complications such as posterior capsule rupture, vitreous loss, and iris trauma is increased. We first reported IFIS as being highly associated with the use of tamsulosin (Flomax), a systemic alpha-1 antagonist and the most widely prescribed treatment worldwide for benign prostatic hyperplasia (BPH). Since then, it has become clear that other systemic alpha-1 blockers such as doxazosin (Cardura), terazosin (Hytrin), and alfuzosin (Uroxatral) can also cause IFIS. Nevertheless, the frequency and severity of IFIS is much less with these nonspecific alpha-1 antagonists than with tamsulosin. This difference probably relates to the much stronger affinity and specificity of tamsulosin for the alpha-1A receptor subtype that predominates in both the prostate and the iris dilator muscle.2,3
Image courtesy David Chang, MD
Figure 1. Classic IFIS.
IFIS can be classified as mild (i.e., good dilation; some iris billowing without prolapse or constriction), moderate (i.e., iris billowing with some constriction of a moderately dilated pupil), or severe (i.e., classic triad and poor preoperative dilation). In one prospective study of 167 eyes in patients taking tamsulosin, the distribution of IFIS severity using this scale was as follows: no IFIS (10%), mild (17%), moderate (30%), and severe (43%) (Ophthalmology. In press). Because there is significant variability in IFIS severity among various patients and even between two eyes of the same patient, it is difficult to conclude whether one management strategy is superior to another. In fact, because the various IFIS techniques discussed in this article can be combined, physicians would do well to master several complimentary approaches.
Pharmacologic Strategies
A variety of pharmacologic methods for managing IFIS have been proposed.2,4-7 Surprisingly, stopping tamsulosin preoperatively is unpredictable and of questionable value. There are many reported cases of IFIS occurring up to several years after tamsulosin had been stopped. As first described by Sam Masket, preoperative atropine drops (e.g., 1% t.i.d. for 1-2 days preoperatively) can provide sufficient cycloplegia to prevent intraoperative miosis (J Cataract Refract Surg. 2006;32:1603-1605). However, atropine alone is often ineffective for more severe cases of IFIS, so this approach is limited as a single strategy. Because of the potential for acute urinary retention, patients should not stop taking tamsulosin without first consulting their urologist. This is particularly true if preoperative atropine is used.
Direct intracameral injection of alpha agonists is an excellent pharmacologic strategy for IFIS. The use of phenylephrine to prevent IFIS was first reported by Packard (Eye. 2007;21:331-332) as was epinephrine by Shugar (J Cataract Refract Surg. 2006;32:1074-1075). By presumably saturating the alpha-1A receptors, these agents can further dilate the pupil and restore iris rigidity, thus increasing the iris dilator smooth muscle tone (Figure 2). By increasing iris rigidity, billowing and prolapse are often prevented. Preserved solutions should be avoided, however, and one must use a diluted mixture (e.g., 1:1000 bisulfite-free epinephrine [American Regent] mixed 1:3 with balanced salt solution [BSS] or BSS+) in order to buffer the acidic pH of the commercial preparation.