Purpose
Although both PRK and LASIK are possible treatment options for high myopia, there have been concerns for development of corneal haze with PRK. The advancement of Mitomycin C (MMC) as a preventative measure in PRK has allowed greater myopic refractive errors to be attempted. This retrospective study specifically compares outcomes of patients with high refractive errors of -7.00 or greater who received LASIK or PRK with MMC. We hypothesized that PRK with MMC is as effective as LASIK and the risks of corneal haze are much lower than previously suggested.
Methods
This retrospective study reviewed charts from TLC locations in Rockville, MD and Tyson's Corner, VA.<br /> All procedures were performed by Dr. Andrew Holzman between 1995-2014. The Wavelight Allegretto Wave 200 Hz excimer laser was used on all patients. A total of 166 eyes (86 LASIK eyes and 88 PRK eyes) with at least a spherical equivalent of -7.00 or greater were reviewed. Any patients with underlying eye disease or previous refractive surgery were excluded. Oucome measures included: uncorrected distance visual acuity, best corrected visual acuity, patient satisfaction, corneal haze, and post-operative complants.
Results
On post operative day 1, vision was better in LASIK patients over PRK with a mean LogMar UCVA of <0.1 (> 20/25) versus 0.4 (20/50) for PRK (p<0.0001). By week 1, there was a much smaller gap in LASIK and PRK patients with uncorrected visual acuity (LogMar) for LASIK patients being 0.05 (>20/25) and <0.2 (>20/30) for PRK patients (P<0.0001). Both LASIK and PRK groups had a mean LogMar UCVA <.0.01 (>20/25) by post op month 1 (P<0.0032). Post op months 3 and 6 showed similar data with both groups having LogMar UCVA <0.1 (>20/25) with p=0.142 and P<0.0033 respectively. Of all patients who underwent PRK, only 4 had any mention of corneal haze. Two of these cases were described as mild. Three of these patients only had haze mentioned at 1 visit, and only one patient had persistent corneal haze at post operative month 11.
Conclusions
LASIK results in better immediate post operataive uncorrected visual acuity in high myopes. By one month post operative, the mean UCVA in both groups was similar and better than 20/25. At 3 months and 6 months, both LASIK and PRK with MMC have excellent results with similar outcomes (> 20/25). PRK with MMC has significantly reduced the presence of corneal haze in high myopes.