Alpha Blockers, Small Pupils Increase Floppy Iris Syndrome

Neil Osterweil

April 10, 2014

TOKYO — The combination of a small pupil, a systemic alpha-1 blocker, and no epinephrine during irrigation significantly increases the risk for intraoperative floppy iris syndrome (IFIS), according to the results of a new masked study.

"If your patient is taking an alpha blocker and they have a small pupil, you should anticipate severe IFIS," said David Chang, MD, clinical professor ophthalmology at the University of California, San Francisco.

Dr. Chang and his colleagues first described the connection between the uroselective alpha-1 blocker tamsulosin (Flomax) and IFIS in 2005 (J Cataract Refract Surg. 2005;31:664-673).

Here at the World Ophthalmology Congress 2014, he reported that the nonselective alpha blocker alfuzosin (Uroxatral) is associated with a lower risk for severe IFIS than tamsulosin, and that epinephrine in the irrigation bottle can help protect against the syndrome.

IFIS is characterized by "poor preoperative pupil dilation, iris billowing and prolapse, and progressive intraoperative miosis," according to an educational update statement issued by the American Society for Cataract and Refractive Surgery and the American Academy of Ophthalmology.

The syndrome is more than a mere annoyance; it increases the difficulty of cataract surgery and can result in vision-threatening complications, such as retinal detachment, lost lens fragments, and endophthalmitis. In addition, IFIS can cause severe iris defects, leading to permanent deformity of the pupil, persistent glare, and photophobia, the statement reports.

Alpha Blockers and IFIS

Dr. Chang and colleagues conducted their controlled masked study to evaluate the effect of alpha blockers on the incidence and severity of IFIS.

Alpha blockers are commonly prescribed for the relief of urinary symptoms associated with benign prostatic hyperplasia, a frequent comorbidity in men with cataracts.

The 113 consecutive patients of 4 cataract surgeons enrolled in the treatment group of the study had been receiving an alpha blocker for a minimum of 3 months; 70 were taking tamsulosin and 43 were taking alfuzosin. The 113 control subjects were operated on by the same surgeons on the same day as the patients in the treatment group, but had never received an alpha blocker.

The surgeons were instructed to avoid using epinephrine for intraoperative irrigation to prevent possible biases. They were allowed to use iris hooks or expansion rings for safety.

All surgeries were performed with a regular phacoemulsification technique, using phenylephrine hydrochloride 2.5% plus either tropicamide 1% or cyclopentolate 1% for mydriasis.

Dr. Chang and another of the investigators reviewed videos of all the procedures, but they were masked to the identity of the surgeon and the drug status. They graded IFIS as none, mild (grade 1; iris billowing only), moderate (grade 2; iris prolapse or significant pupil constriction during surgery), or severe (grade 3; billowing, prolapse, and constriction).

The combined incidence of moderate to severe IFIS was 12.4% in the control group, 55.7% in the tamsulosin group (P < .001), and 39.5% in the alfuzosin group (< .001).

The risk for grade 3 IFIS was nearly 4-fold higher in patients with presurgical pupils 5.0 to 7.5 mm in diameter than in those with pupils 8.0 to 10.0 mm in diameter (odds ratio, 3.80; 95% confidence interval, 1.09 - 13.26; P = .04).

The incidence of grade 3 IFIS was 34% in the tamsulosin group, 16% in the alfuzosin group, and 4% in the control group.

Dr. Chang acknowledged that the incidence of severe IFIS in the control group was a surprise, and has not previously been reported.

To see whether this was related to the lack of epinephrine in the irrigation bottle, the investigators looked at the incidence and severity of IFIS in a series of 127 consecutive patients not taking an alpha blocker who did not receive irrigation with epinephrine. They found that the rates of mild, moderate, and severe IFIS were similar to those seen in the treatment groups in their study.

This suggests that epinephrine is important for maintaining pupil size during cataract surgery, and that patients on an alpha blocker require special handling, Dr. Change explained.

For a patient with a cataract who needs a safe alpha blocker with a low risk for cardiovascular events, "it would make sense that you start with alfuzosin first," he said.

This study provides important information about avoiding complications of severe IFIS, said Thomas Kohnen, MD, chair and professor of ophthalmology at Goethe University in Frankfurt, Germany.

"I think this will become a bigger problem in the future as we have more patients who take these medications and have more cataracts to do," he told Medscape Medical News.

"This study shows that we have to use epinephrine during cataract procedures so that the pupils do not get too constricted," Dr. Kohnen said.

Dr. Chang and Dr. Kohnen have disclosed no relevant financial relationships.

World Ophthalmology Congress (WOC) 2014: Abstract FP-TH-06-2. Presented April 3, 2014.

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