Custom LASIK systems both fare well in comparison study

December 15, 2004

New York-A comparison of CustomCornea (Alcon Laboratories Inc.) and CustomVue (VISX) indicated that both systems provided excellent visual outcomes, with most eyes gaining one or more lines of best-corrected visual acuity (BCVA).

New York-A comparison of CustomCornea (Alcon Laboratories Inc.) and CustomVue (VISX) indicated that both systems provided excellent visual outcomes, with most eyes gaining one or more lines of best-corrected visual acuity (BCVA).

More patients in the CustomCornea group achieved better than 20/20 vision, which may be attributable to undercorrection in the CustomVue group, according to Mark Speaker, MD, PhD, medical director, TLC Manhattan, New York.

The investigators evaluated the visual outcomes (without re-treatment) of the first 100 eyes at 6 months after treatment with one of the systems for uncorrected visual acuity, induced higher-order aberration, and gains and losses of BCVA.

The spherocylindrical data in both groups were similar (sphere, 3.6 D in the CustomCornea group and 2.48 D in the CustomVue group; cylinder, 0.62 and 1.19 D, respectively).

The CustomCornea system uses a 6.5-mm treatment zone and the CustomVue system 6 mm. All flaps were 100 µm and were created using an LSK1 microkeratome (Moria).

The customized treatments required longer ablation times, Dr. Speaker pointed out, and he spends more time drying and smoothing the flaps as a result of the added ablation time.

"On postoperative day 1, 82% of the CustomCornea group had 20/20 or better visual acuity and in the CustomVue group 75% had 20/20 or better visual acuity. At 1 month, the percentages increased, respectively, to 92% and 95%, and at 6 months, the percentages were 100% and 99%, respectively," Dr. Speaker reported.

Sixty-two percent of eyes in the CustomCornea group and 42% in the CustomVue group achieved better than 20/20 vision; six eyes in the CustomVue group were undercorrected, which may explain the difference in the percentages between the two systems.

Six percent of eyes treated with the CustomCornea system had better than 20/15 vision; no eyes in the CustomVue group had better than 20/15 vision.

Regarding the change in BCVA 6 months after surgery, one eye in the CustomVue group lost one line of BCVA. Sixty-three percent and 42% of eyes, respectively, in the CustomCornea group and the CustomVue group gained one or more lines of BCVA.

Regarding higher-order aberrations, Dr. Speaker noted that differences in the two systems were apparent because in the CustomCornea system the measurements are done through a dilated pupil, which produces higher root mean square values. In addition, doing measurements through small pupil diameters may create inaccuracies and mask some induced higher-order aberrations.

"There was about a 20% increase in total higher-order aberrations in both groups, which approached significance in the CustomVue group," he said.

"The customized ablations using both platforms produced superior results. At 6 months postoperatively, there was a higher percentage of eyes with better than 20/20 vision in the CustomCornea group," he said. "This could be explained by undercorrections in the CustomVue group. This difference between the two groups may resolve when we analyze the later data.

"The CustomVue results were highly dependent on control of accommodation during data acquisition and nomogram adjustment. Most of our eyes gained one or more lines of BCVA, which was gratifying. All eyes achieving an uncorrected visual acuity of 20/15 or a gain of two lines of BCVA were treated with CustomCornea. In my experience, greater attention to flap drying and smoothing is critical for delivering outstanding custom results provided by these platforms," Dr. Speaker said.