Abstract

Propose: The aim of this study was to evaluate and compare the results of two devices with different repetition rates (100Hz Vs. 500Hz) in Photorefractive keratectomy (PRK) surgery.

Methods: In this research, we studied post-operative outcomes of PRK surgeries performed with two different repetition rates (100 and 500Hz). One-hundred-ten patients underwent PRK, 110 eyes with Technolas 217z100 and 110 eyes with Technolas 317. After 6 months uncorrected distant visual acuity (UCDVA), best-corrected distant visual acuity (BCDVA), refraction and wave-front aberrometry were compared between two groups.

Results: Ninety-four eyes (85.45%) in the 100Hz group and 98 eyes (89.09%) in the 500Hz group had a UCDVA of 20/20 or better at the last follow-up examination. The mean SE attempted correction was -3.68D±1.66 in 100Hz group and -3.80D±1.46 in 500Hz group respectively. About high order aberrations (HOAs), The mean of vertical coma, was 0.031±0.241μm in group 100Hz, and -0.062±0.285μm in group 500Hz. Mean postoperative vertical coma was significantly different between two groups (P=0.033). The vertical trefoil, horizontal trefoil and horizontal coma were not significantly different between the groups (P>0.05).

Conclusion: Both excimer laser systems were effective, improving the UCDVA in comparison with the pre-operation UCDVA. The results showed that Technolas 217z100 (100Hz repetition rate) in PRK surgeries might have better visual quality outcome.

Keywords: Photorefractive keratectomy; Myopia; Excimer laser; Refractive surgery; Ocular aberrations