Study tracks incidence, risk factors in floppy iris syndrome

Charleston, SC-A large study of routine phacoemulsification found the total incidence of intraoperative floppy iris syndrome (IFIS) to be 3.8%. In addition to the use of tamsulosin (Flomax, Boehringer Ingelheim Pharmaceuticals) before surgery, angiotensin antagonists and saw palmetto also were implicated in the development of IFIS.

More than 6 months after the use of tamsulosin has been discontinued, IFIS still can be present, according to Kristiana D. Neff, MD.

"Floppy iris syndrome was first described by David F. Chang, MD, and John Campbell, MD, as a new small-pupil syndrome associated with the use of tamsulosin, the systemic alpha-1a antagonist," Dr. Neff recounted. "Drs. Chang and Campbell described a triad of characteristics: a flaccid iris stroma that undulates and billows, a tendency for the iris stroma to prolapse toward surgical wounds, and progressive intraoperative miosis."

"The investigators found that the total incidence of IFIS was 3.8% of subjects (16 of 418 patients) with no significant variability between surgeons. This incidence was consistent with previously published studies. Of these 16 patients, 88% were men, which is about twice that of the total patient population," she reported.

"We identified IFIS in 8% of men and 0.8% of women," Dr. Neff said.

When the investigators compared the medical histories of the total patient population, diabetes, hypertension, and congestive heart failure were not found to be associated with IFIS.

"When we evaluated the group of men alone, hypertension was found to be a statistically significant variable for the development of IFIS," Dr. Neff reported.

When she and her colleagues evaluated the medications used at the time of surgery, they identified that tamsulosin was used in 36% of patients with IFIS, compared with 1% of patients who did not have IFIS (p < 0.0001).

Interestingly, the investigators also identified four other drugs that were used more often in the patients in whom IFIS was manifesting, including angiotensin antagonists, saw palmetto, other alpha-1 antagonists, and muscle relaxants, she said. "However, only the use of angiotensin antagonists [p = 0.004] and saw palmetto [p = 0.01] reached significance," Dr. Neff reported.

In addition to these drugs, the investigators also evaluated the patients who had discontinued tamsulosin 6 months or more before surgery.

"We found that a high percentage of the patients with IFIS were among those patients," she stated.

Among the study patients were two women in whom IFIS had manifested; neither had ever taken an alpha-1 antagonist. Both women were taking an angiotensin antagonist at the time of surgery.

One man in the study group had discontinued tamsulosin 6 months before surgery and was taking a muscle relaxant at the time of surgery. He was noted to have IFIS during the first cataract surgery. He subsequently discontinued the muscle relaxant before his next cataract surgery and did not manifest IFIS in the second eye.

"The results of this study indicate that the incidence of IFIS compares with previously reported data," Dr. Neff pointed out. "Tamsulosin still appears to be implicated as a causative factor in this syndrome. However, only 63.6% of all of our patients who were taking tamsulosin at the time of cataract extraction or had a history of tamsulosin use actually manifested IFIS during surgery. In addition, only 43.5% of patients who had IFIS had ever used tamsulosin."

The investigators also observed an association with other drugs and IFIS.

"Further analysis is needed to determine the exact role the drugs play in the syndrome," Dr. Neff said.