Relationship between cycloplegic and wavefront-derived refraction.

PURPOSE: To compare cycloplegic refractions to preoperative wavefront-derived refractions from three Hartmann-Shack-based wavefront devices.

METHODS

Ninety-nine eyes of 55 subjects were evaluated preoperatively using the LADARWave, WaveScan, and Zywave aberrometers. With cycloplegic refraction as the standard, the spherical equivalent refraction, sphere, and cylinder were compared to the wavefront-derived refractions using the three wavefront devices.

RESULTS

The LADARWave unit showed the highest correlation between wavefront-derived sphere and mean spherical equivalent refraction values relative to cycloplegic refraction, followed by Zywave and WaveScan. The WaveScan unit exhibited higher variability than the LADARWave or Zywave. Although Alcon Laboratories (LADARWave) and Bausch & Lomb Surgical (Zywave) recommend dilation, VISX specifically recommends against dilation in their WaveScan unit. All devices showed high cylinder error vectors when the cycloplegic cylinder was greater than 1.00 D.

CONCLUSION

Although wavefront-derived refractions appeared to correlate well to cycloplegic refractions, further research is required to reduce variability and improve the calculation of cylinder terms.