Investigational phakic IOL for high myopia promising

March 15, 2007

London-An angle-supported phakic refractive IOL (AcrySof, Alcon Laboratories) offers patients with high myopia stable and accurate refractive results with excellent visual acuity as well as no safety concerns, according to physicians who presented data here at the XXIV Congress of the European Society of Cataract and Refractive Surgeons.

The first single-piece, foldable lens of this brand had a 5.5-mm optic, an overall length of 12.5 to 13.5 mm, and a dioptric range of –8 to –16.5 D and was implanted by Michael C. Knorz, MD, professor of ophthalmology, University Medical Center Mannheim, Mannheim, Germany. He presented the long-term clinical results from the phase I European clinical trial of the lens after 5 years.

Dr. Knorz and Joseph Colin, MD, professor and chairman, CHU de Bordeaux, Hôpital Pellegrin, Bordeaux, France, were the two investigators in the open-label, single-arm, dual-center phase I European trial of the phakic IOL. The lens was implanted unilaterally in 10 patients using a specific IOL delivery system (Monarch I, Alcon Laboratories). Nine of 10 patients were followed for 5 years and one patient was lost to follow-up.

Patients selected for inclusion in the phase I European trial had to be aged at least 21 years, have stable myopia greater than or equal to 8 D, an anterior depth of 3.0 mm or greater, and less than 2 D of preoperative astigmatism. They could not have a mesopic pupil greater than 6.0 mm and endothelial cell density had to equal or exceed 2,500 cells/mm2 .

The mean manifest refractive spherical equivalent (MRSE) for the patient population was –11.35 D preoperatively, improved to –0.5 D at 1 day postop, and was –0.79 D at 6 months postop, –0.86 at 1 year postop, and –0.88 D at 5 years, Dr. Knorz noted. At 5 years postoperatively, the refractive predictability was met for the percentage of eyes within ±0.5 D of intended MRSE, 57%, and was slightly lower for the percentage of eyes within ±1.0 D of intended MRSE, 71%. The FDA guidance criterion was 50% within ±0.5 D of intended MRSE and was 75% within ±1 D of intended MRSE. Although, statistically, this is not too meaningful for nine eyes, Dr. Knorz noted.

Uncorrected visual acuity (UCVA) at 5 years was 20/20 or better in 55.6% of eyes and 20/40 or better in 88.9% of eyes. Best-corrected visual acuity during this period was excellent, with 66.7% of the eyes achieving 20/20 or better and 100% of the eyes achieving 20/25 or better.