Differences in phakic lens design may explain HOA differences, researcher says

April 28, 2007

Technical differences in lens design may explain the variation in higher-order aberrations (HOAs) seen 1 year after implantation of a phakic IOL (Artisan, Ophtec) compared with a flexible version of the lens (Artiflex, Ophtec), reported Nayyirih G. Tahzib, MD, an ophthalmologist practicing at University Hospital Maastricht, Maastricht, Netherlands.

Technical differences in lens design may explain the variation in higher-order aberrations (HOAs) seen 1 year after implantation of a phakic IOL (Artisan, Ophtec) compared with a flexible version of the lens (Artiflex, Ophtec), reported Nayyirih G. Tahzib, MD, an ophthalmologist practicing at University Hospital Maastricht, Maastricht, Netherlands.

Dr. Tahzib and colleagues studied 27 eyes of 14 patients who underwent implantation of the flexible lens for the correction of myopia. Mean patient age was 41 ± 7.8 years (range, 26 to 51 years), and the mean spherical equivalent (SE) was –9.95 ± 1.43 D (range, –6.75 to –12.13 D).

The researchers recorded HOA values obtained via a wavefront aberrometer (Zywave, Bausch & Lomb) before surgery and 1 year postoperatively, and the values were correlated. They compared these HOA values with ones recorded for 22 eyes of 13 patients who received the non-flexible implantable contact lens for the correction of myopia. Members of that group had a mean age of 40 ± 12 years (range, 18 to 52 years) and a mean SE of –9.89 ± 2.74 D (–4 to –14.50 D).

The mean preoperative and postoperative spherical aberration (SA) values in the flexible implant group were 0.29 µm and 0.03 µm, respectively (p = 0.001). Mean preoperative and postoperative SA values in the non-flexible implant group were 0.19 µm and 0.60 µm, respectively (p = 0.001).

"This was a small study and, unfortunately, at this time, we don't have an explanation for the differences in SA patterns," Dr. Tahzib said. The variation may be related to differences in the designs of the lenses, including the incision sizes required for insertion and the optic materials, she added. "We hope to present new results next year."