Evaluation of Corneal Keratometry in Relation to Spherical Equivalent After Excimer Laser Photoablation Using Wavefront-Optimized and Wavefront-Guided Platforms
Purpose
To identify a relationship between change in keratometry (K) and change in spherical equivalent (SE) after excimer laser photoablation using wavefront guided and wavefront optimized platforms.
Methods
The data from 1064 eyes that had LASIK or PRK was analyzed. Four-hundred twenty-four were treated with the VISX Star S4 IR platform, and 640 were treated with the Wavelight Allegretto platform. The ratio of absolute change in spherical equivalent (∆SE= |SEpreop- SEpostop|) to change in keratometry (∆K=Kavg.(preop)-Kavg. (postop)) was calculated. This ratio was compared based on low, moderate, and high∆SE as well as by refractive surgery type and platform.
Results
The ∆K/∆SE varied by comparison. At 3 months, Allegretto LASIK and VISX LASIK showed no significant difference at low, moderate, and high ∆SE. Allegretto PRK and VISX PRK were not significantly different, except at the moderate ∆SE. The comparison of VISX PRK and VISX LASIK as well as Allegretto PRK and Allegretto LASIK were significantly different at high ∆SE only.
Conclusion
In both the VISX and Allegretto platforms, PRK and LASIK ∆K/∆SE values were significantly different at high ∆SE only.