San Francisco-DisCoVisc (Alcon Laboratories) performs better than Healon 5 (Advanced Medical Optics) during cataract surgery in patients who have been taking tamsulosin HCl (Flomax, Boehringer Ingelheim), which is a culprit in the intraoperative floppy iris syndrome (IFIS), according to Satish Modi, MD, FRCS (C).
In addition, a second study conducted by Shetal Raj, MD, found that the ophthalmic viscosurgical device (OVD) showed both cohesive and dispersive properties during difficult surgeries that included dense cataract, white cataract, shallow anterior chamber, small pupils, and compromised corneas. Drs. Modi and Raj reported their findings at the annual meeting of the American Society of Cataract and Refractive Surgery.
IFIS is characterized by marked floppiness of the iris, miosis that progresses over time during the cataract surgery, and iris prolapse into the wound throughout the procedure.
Dr. Modi who is in private practice in Poughkeepsie, NY, pointed out that stopping tamsulosin does not help. "In fact, the surgeon may get 'bushwhacked,' because often patients do not report that they were taking tamsulosin 6 months to 1 year before the surgery. This can lead to an intraoperative surprise when the iris becomes floppy," he emphasized.
The miosis associated with IFIS is not prevented by dilation with agents such as tropicamide, cyclopentolate, and atropine once the intraocular procedure has started. Pupillary stretching does not prevent miosis later in the procedure.
"Viscomydriasis with Healon 5 has been advocated, but this is with low-flow phacoemulsification parameters," he said. "Two-thirds of phaco surgeons use high flow during surgery. It makes sense not to change the surgical technique and use a viscoelastic that works well with our technique, rather than modifying the technique to match a particular viscoelastic."
Dr. Modi and colleagues conducted a study to see which OVD works best in these patients who underwent cataract surgery using high-flow phacoemulsification. DisCoVisc, a viscous-dispersive OVD, was compared with Healon 5, a super-cohesive OVD, to determine which provides better protection and visibility in complicated cataract cases where the patient was taking or had taken tamsulosin. All patients included in the prospective study underwent bilateral cataract surgery and all used tamsulosin. One eye of each patient was randomly assigned to Healon 5 and the other eye to DisCoVisc.
All patients underwent pupillary dilation with one of the following: 2.5% phenylephrine HCl (Neosynephrine), 1% tropicamide (Mydriacyl), and 1% cyclopentolate drops. The Infiniti Vision System (Alcon Laboratories) was used in all cases. Quadrant removal was performed with 55 ml of flow and 500 mm Hg vacuum. There was no mechanical pupillary manipulation in any case.
Dr. Modi reported the preliminary results from eight eyes of four patients. Most patients were in their mid-70s. "Intraoperatively, we noticed that six of the eight eyes had iris prolapse consistently throughout the procedure. Seven of eight had miosis requiring viscomydriasis. DisCoVisc required one injection, but Healon 5 required repeated injections because it came out of the eye," Dr. Modi reported.
Two of the eight eyes had round capsular tears, all of which occurred with Healon 5. One of eight had severe iris chafing and burning because the floppy iris was trapped in the phaco tip; this patient developed cystoid macular edema (CME) postoperatively.
Ninety days after the surgery, seven of the eight patients have 20/20 vision. One of eight has 20/40 because of the CME and still has severe iris chafing.