Alteration in Corneal Hysteresis After LASIK and PRK
To evaluate the effect that both LASIK and PRK have on the corneal viscoelasticity using the Ocular Response Analyzer (Reichert Ophthalmic Instruments).
The data from 222 patients, 140 who had LASIK and 82 who had PRK, was analyzed prospectively after IRB approval. The selection process for LASIK and PRK was based on safety as well as the patient's preference. Corneal hysteresis (CH), corneal resistance factor (CRF), and corneal topography were obtained preoperatively. They were followed at 3, 6, and 12 month intervals. At each follow up visit, CH and CRF were measured for significant changes along with a corneal topographic analysis.
The alteration of corneal viscoelasticity decreased significantly postoperatively in both LASIK and PRK groups. However, the change in CH was not significantly different amongst the LASIK and PRK groups in the 3, 6, and 12 month time periods.
Both LASIK and PRK cause a significant decrease in CH. However, the degree of change is not significant when LASIK is compared to PRK.