Floppy iris syndrome not definitively linked to alpha-blockers in study

ByMichela Cimberle

LONDON — Intraoperative floppy iris syndrome is not always associated with the use of alpha-blockers such as tamsulosin, according to a study conducted by Aditi Molha, MD, and colleagues.

“Our results show that not all the patients who develop intraoperative floppy iris syndrome (IFIS) 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,” Dr. Molha said during the United Kingdom and Ireland Society for Cataract and Refractive Surgeons (UKISCRS) meeting.

David F. Chang, MD, and John Campbell, MD, described IFIS. It is characterized by a tendency of the iris to prolapse through the cataract incision, and it is associated with poor preoperative pupil dilation and progressive intraoperative miosis. In their study on 1,600 patients, Drs. Chang and Campbell said they found “overwhelming evidence” that IFIS is caused by alpha-blockers, the most popular of which is Flomax (tamsulosin, Boehringer Ingelheim).

Dr. Molha and coworkers further investigated the incidence of IFIS by surveying their colleagues.

“At the Huddersfield Royal Infirmary, we collected data through a questionnaire sent to cataract surgeons. They did not know that we were investigating IFIS, but answered a series of questions concerning the behavior of the iris and pupil during each of their cataract procedures. The answers gave us the opportunity to evaluate a total of 151 patients, of whom 12 (8%) were on alpha-blockers,” Dr. Molha explained.

In this series of patients, poor pupil dilation occurred in eight patients (5%), one of whom was taking an alpha-blocker. Intraoperative pupil constriction was seen in 11 patients (7%), three of whom were taking an alpha-blocker. A loss of iris tone was seen in 14 patients (9%), of whom five were on alpha-blockers. And iris prolapse occurred in 11 patients (7%), of whom four were on alpha-blockers.

“In conclusion, according to the results of our study, IFIS and alpha-blocker use can be associated, but not invariably so. 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 for the surgery,” Dr. Molha said.

Surgeons increasingly using intracameral triamcinolone

An increasing number of surgeons are using or are interested in using intracameral triamcinolone during complex anterior chamber surgery, a surgeon said.

For some time after the technique was first described 4 years ago, there was some reluctance in using it, said Romesh Angunawela, MD, who presented a video on the topic. This reluctance was due mostly to fear of complications and misconceptions regarding the preparation of the substance, he said.

“In actual fact, triamcinolone for anterior segment use is easy to prepare, doesn’t need filtration, and there is no evidence that it may cause significant complications,” Dr. Angunawela said. “It is a simple technique for visualizing the vitreous and guiding your vitrectomy, and ultimately it makes complicated cataract surgery safer.”

Intracameral triamcinolone is invaluable in determining not only the presence but also the absence of vitreous in the anterior segment, he said.

“It visualizes the vitreous strands so that you can guide your vitrector exactly to where they are and deal with them completely and safely under visualization. It’s a guided technique, much safer than just sweeping around with the vitrector,” he said.

Wrong-site surgery preventable with precautions

Wrong-site surgery can be prevented if appropriate procedures are used for verification, said Adeel Shaikh, MD, of the Royal Eye Infirmary in Plymouth, England.

“Our hospital protocol, implemented in 2001, has resulted in elimination of wrong-site surgery in spite of high-volume activity,” he said.

The protocol used at the hospital requires that the consent form, operating notes and doctor’s order for preoperative medications must all be available in the operating room. The protocol also requires that the skin be marked next to the eye undergoing surgery and that the patient must confirm which eye is to be treated immediately before the procedure.

Before every procedural stage (administration of eye drops or medications, anesthetic injection, sedation and incision), the nurses, anesthesiologists and surgeons also double-check the consent, case notes, skin mark and patient’s answer, establishing that they all match. If there is any discrepancy, the surgeon makes the final decision, and the discrepancy is corrected and reported.

“During the 5-year period between 2001 and 2005, there were approximately 17,000 eye procedures performed in our hospital,” Dr. Shaikh said. “Two near-miss incidents were reported, one of a wrong procedure on the operating list as compared to the patient’s case notes and the other of the wrong side. Both were identified by the nursing staff … prior to the patient being transferred to the operating theater. A third case was an incidental instillation of preoperative eye drops in the other eye."

Aloe-vera-derived sugar inhibits corneal scarring

A macromolecular sugar derived from aloe vera is a safe, cheap, nontoxic and potentially therapeutic agent for prevention of scarring and haze following corneal refractive surgery, according to Romesh Angunawela, MD.

Dr. Angunawela, of St. Thomas’s Hospital, London, studied the use of the aloe-vera-derived sugar, mannose-6-phosphate (M6P) in refractive surgery.

“Key to the scarring and haze formation following corneal injury is the transformation of passive keratocytes into fibroblasts and in particular myofibroblasts,” he said. “This process is typical of the human adult organism, while in the embryo healing occurs without scarring.”

The balance between scar-free regenerative healing and healing with scarring hinges on the mix of cytokines released during tissue injury, and in particular on the TGF-beta family of cytokines, he explained.

“TGF is an obvious target for the modulation of corneal wound healing,” the surgeon said.

“The M6P, which binds competitively to the same cell receptor as the TGF-beta family, competitively antagonizes its pro-scarring actions and therefore reduces or stops scarring in the skin.”

The effects of M6P were investigated in cultured human corneal cells.

“M6P proved to significantly inhibit the effect of TGF-beta on corneal keratocytes, suppressing their differentiation to myofibroblasts. The difference between groups was statistically significant, Dr. Angunawela said.

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Michela Cimberle is an OSN Correspondent based in Treviso, Italy, who covers all aspects of ophthalmology. She focuses geographically on Europe.