A disposable pupil expansion device (Malyugin, MicroSurgical Technology) was evaluated in a series of 30 consecutive eyes of 21 patients taking tamsulosin (Flomax, Boehringer Ingelheim Pharmaceuticals) at the time of cataract surgery. The experience showed the device was easy to insert and remove. It maintained a 6.0-mm round pupil without causing significant iris trauma and allowed the surgeries to be completed without significant complications.
Dr. Chang, clinical professor of ophthalmology, University of California, San Francisco, reported on his experience using this newest addition to marketed pupil expansion rings. During a 5-month period in 2007, 30 consecutive eyes in 21 patients with a history of tamsulosin (Flomax, Boehringer Ingelheim Pharmaceuticals) use were operated on after receiving a standard preoperative dilating regimen but no additional strategies other than the ring to mitigate the effects of IFIS. All procedures were performed with Dr. Chang's routine, high-flow (38 ml per minute), high-vacuum (400 mm Hg) phaco parameters.
Caliper measurements taken intraoperatively showed the pupil expansion device reliably maintained a 6.0-mm, rounded pupil diameter, and the surgeries were completed without any cases of capsular rupture. One eye developed minor bleeding, and iris prolapse to the corneal incision or side port occurred in 13 eyes but also was minor. Best-corrected visual acuity was 20/25 or better in all eyes 1 month after surgery.
The ring is constructed of 5-0 polypropylene (Prolene, Ethicon) and is placed using a disposable, two-part injector system. It is intended for use in eyes with a pupil diameter <6.0 mm.
"If the pupil diameter is larger, the ring will not engage the iris," Dr. Chang added.
The device has a square configuration and features a coiled scroll at each of its corners. The insertion is performed after the eye is filled with viscoelastic. Once the device is expelled from the inserter, the iris at the contra-incisional margin is engaged with the lead scroll. If the pupil is small enough, however, the iris margin can be engaged with one or both lateral scrolls. A blunt, Lester-type positioning hook is used to position the other three scrolls. After the IOL is implanted, the removal is done very efficiently using the injector device.
The 30 eyes in Dr. Chang's study had a mean preoperative pupil diameter of 5.1 mm (range, 2.5 to 6.5 mm) and a mean final intraoperative pupil diameter of 3.0 mm (range, 2.5 to 4.0 mm). All patients continued taking tamsulosin, and neither viscoadaptive nor intracameral epinephrine were used intraoperatively. Based on a grading system of IFIS severity developed in a previous multicenter study of 167 consecutive eyes, 93% of the 30 eyes were considered to have moderate/severe IFIS.
"In the large population of eyes in the multicenter trial that was the basis for this grading system, about three-fourths of eyes had mild to moderate IFIS. The greater severity of IFIS in eyes in the . . . ring series is consistent with the fact that patients whose pupils dilated well preoperatively were excluded from the study," Dr. Chang said.