Abstract
Purpose: :
To test reproducibility of lower– and higher–order aberration measurements using the Alcon LADARWave system
Methods: :
Measurements were obtained using the LADARWave device from one hundred eyes (50 patients) who presented for refractive surgery. Two different measurements were taken a minimum of one day apart. Zernicke polynomial values for the two separate measurements were recorded; reproducibility was assessed by analyzing the mean difference between the two measurements.
Results: :
The mean difference for defocus was 0.17 +/– 0.12 microns, which represented 2.6% +/– 1.9% of the mean defocus value (6.33 microns). The mean difference for astigmatism was 0.11 +/– 0.12 microns, which represented 23% +/– 26% of the mean astigmatism value (0.45 microns). The mean difference for coma was 0.06 +/– 0.06 microns, which represented 37% +/– 37% of the mean coma value (0.16 microns). The mean difference for spherical aberration was 0.04 +/– 0.04 microns, which represented 18% +/– 18% of the mean spherical aberration value (0.22 microns).
Conclusions: :
LADARWave measurements for defocus were very reproducible, while measurements of astigmatism and higher–order aberrations were more variable. LASIK techniques which utilize wavefront principles offer the theoretical advantage of correcting both lower– and higher–order aberrations. Correction of these aberrations is dependent upon reproducible and precise measurement of these terms, which is very difficult to achieve clinically. While the current LADARWave system leads to excellent visual outcomes, in order to fully realize the benefits of wavefront–guided LASIK, a device that measures aberrations more reproducibly is needed.
Keywords: refractive surgery: other technologies • refractive surgery: LASIK • clinical (human) or epidemiologic studies: systems/equipment/techniques