Abstract
PurposeTo compare the results of laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) for myopia using a mixed-effects model.MethodsThis comparative retrospective study was conducted in 1,127 eyes of 579 patients after LASIK and 270 eyes of 144 patients after PRK who had two or more postoperative follow-ups after 3 months. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refractive spherical equivalent (MRSE), percentage of eyes within ± 0.5 diopters (D) and ± 1.0 D of targeted refraction, and central corneal thickness were compared between PRK and LASIK groups using a mixed-effects model.ResultsCompared with the LASIK group, UCVA in the PRK group was significantly worse in the initial year but was significantly better after 4 years. The average BSCVA was not significantly different between the LASIK and PRK groups after 4 years. The average gain of BSCVA in the PRK group was significantly larger than that of the LASIK group after 2 years. MRSE in the LASIK and PRK groups showed a gradual myopic shift until 6 years after surgery. After 6 years, MRSE in the PRK group remained stable whereas MRSE in the LASIK group continued a myopic shift. The percentages of eyes within ± 0.5 D or ± 1.0 D in the LASIK group were significantly higher than those in the PRK group at 3 months but were significantly lower than those in the PRK group at 10 years.ConclusionsPRK for myopia shows better efficacy than LASIK for myopia after 4 years.
Highlights
Laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) have been the most frequently performed refractive surgeries, and the results of long-term follow-ups as long as 10 years have been reported.[1,2,3,4,5,6,7,8,9,10,11] Some of these previous studies involved only patients who completed the long-term follow-up
LASIK was performed from March 2000 to March 2015, and PRK was performed from May 1998 to July 2013
After 6 years, manifest refractive spherical equivalent (MRSE) in the PRK group remained stable whereas MRSE in the LASIK group continued a myopic shift
Summary
Laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) have been the most frequently performed refractive surgeries, and the results of long-term follow-ups as long as 10 years have been reported.[1,2,3,4,5,6,7,8,9,10,11] Some of these previous studies involved only patients who completed the long-term follow-up. A selection bias likely occurs when patients with missing data or incomplete follow-ups are excluded. The mixedeffects model has been used for analyses of longitudinal clinical data to reduce the bias involving selected or missing data. We conducted a study to compare the results of LASIK and PRK using this model
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