Purpose:
To assess the optical quality of the cornea after wavefront-optimized photorefractive keratectomy (WFO PRK) and WFO LASIK.
Methods:
In a prospective, non-randomized, controlled trial, 143 patients with myopia or myopic astigmatism underwent either WFO PRK (n=73; 146 eyes) or LASIK (n=70; 139 eyes) at the Walter Reed Center for Refractive Surgery. Epithelium debridement was done using the Amoils brush (Innovative Excimer Solutions) in PRK and the superior-hinged flap was created with the Intralase femtosecond laser system (Abbott Medical Optics) in LASIK. All photoablations were performed using the ALLEGRETTO WAVE Eye-Q 400 MHz laser platform (Alcon Surgicals). The following TMS-4 corneal topography (Tomey) indices were used to assess optical quality: surface regularity index (SRI), surface asymmetry index (SAI), and irregular astigmatism index (IAI). Repeated measures analysis of variance was used to compare WFO PRK to WFO LASIK. PRK eyes treated with mitomycin-C were excluded from the analysis and a P value <0.05 was considered significant.
Results:
Mean topography indices of WFO PRK vs. WFO LASIK are listed on Table 1. There was a statistically significant difference between WFO PRK vs. WFO LASIK in measures of SRI (P<0.001) and IAI (P=0.001). There was no significant difference in SAI (P=0.20) between the two groups postoperatively. Uncorrected distance visual acuity was not significantly different between the two groups while corrected distance visual acuity was better after WFO PRK than WFO LASIK.
Conclusions:
In the quantitative assessment of the optical quality of the cornea, wavefront-optimized PRK appeared to be superior to wavefront-optimized LASIK. This finding translated to better postoperative corrected visual acuity in PRK than LASIK. Postoperative uncorrected visual acuity was comparable.
Clinical Trial:
http://www.clinicaltrials.gov NCT00411827
Keywords: refractive surgery: optical quality • refractive surgery: PRK • refractive surgery: LASIK