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Floppy iris not related only to alpha-blockers, study shows
Not all patients who developed a floppy iris during cataract surgery were taking alpha-blockers.
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LONDON — Intraoperative floppy iris syndrome is not always associated with the use of tamsulosin or other systemic alpha-blockers, according to a study carried out at the Huddersfield Royal Infirmary, U.K.
“Our results show that not all the patients who develop intraoperative floppy iris during cataract surgery are on alpha-blockers and that, conversely, as many as 60% of the patients who are on alpha-blockers don’t develop a floppy iris,” Aditi Mohla, MD, said.
Intraoperative floppy iris syndrome (IFIS) was first described by David Chang, MD, and John Campbell, MD. Its main manifestation is a repeated tendency of the iris to prolapse through the incisions during cataract surgery, often associated with progressive intraoperative myosis and with poor dilation of the pupil preoperatively.
In their study of 1,600 patients, Drs. Chang and Campbell found “overwhelming evidence” that IFIS is caused by tamsulosin hydrochloride, otherwise called Flomax (Boeheringer Ingelheim), Dr. Mohla said.
“Flomax is a systemic alpha-1 antagonist. As a smooth muscle relaxant, it is commonly used in the treatment of benign prostatic hypertrophy and hypertension. It has a high selectivity for alpha-1 receptors, which are also the predominant receptors of the iris dilator muscle,” Dr. Mohla said.
Not always related
“We carried out a prospective, randomized, masked study in order to see how strong the correlation is between floppy iris syndrome and systemic alpha-blocker use,” Dr. Mohla said.
The data of 151 patients were collected. The mean patient age was 78 years (range, 41 to 93 years).
Of the 151 patients, a poorly dilated pupil before surgery was reported in eight cases (5%), of which one was on an alpha-blocker. Progressive pupil constriction during surgery was seen in 11 patients (7%), of which three were on an alpha-blocker. The iris tone was floppy in 14 patients (9%), of which five were on an alpha-blocker, and iris prolapse occurred in 11 patients (7%), of which four were on an alpha-blocker.
Only 8% of patients were taking alpha-blockers, and 60% of these patients did not develop IFIS.
Medications should not be discontinued
“Firstly, we can conclude that the use of alpha-blockers is not as common as may be perceived in the population. We can also say that floppy iris and alpha-blockers’ use can be associated but not invariably so. And, more importantly, we found that floppy iris can occur in patients who are not on alpha-blockers,” Dr. Mohla said.
Other causes of IFIS should be investigated in the future, but what is certain for now is that “it is not just Flomax,” Dr. Mohla added.These conclusions suggest that cataract surgeons should be prepared for IFIS in all cases, irrespective of whether the patients are taking alpha-blockers. However, surgeons should not be alarmed if patients are taking alpha-blockers because floppy iris is not inevitable.
“In view of these findings, we would not recommend discontinuing the use of these medications prior to surgery, as this might cause significant symptoms to the patients without any real benefit to the surgery,” he said.
For more information:
- Aditi Mohla, MD, can be reached at 2 Sharp Mews, Leeds LE6 2SE, United Kingdom; e-mail: aditi_mohla@yahoo.com.
- Michela Cimberle is an OSN Correspondent based in Treviso, Italy, who covers all aspects of ophthalmology. She focuses geographically on Europe.