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Epi-LASIK provides slightly better refractive outcomes 3 months postoperatively compared with standard LASEK, which may be due to the quicker and smoother separation of the epithelial layer from Bowman's membrane and the absence of alcohol with its negative effect on energy absorption of the excimer laser.
Munich, Germany-Epi-LASIK seems to provide better visual outcomes compared with standard LASEK in that it allows faster and smoother separation of the epithelial layer, according to Carlo Lackerbauer, MD.
"Surface ablation treatments have undergone a renaissance in the last few years," Dr. Lackerbauer stated. "There are some reasons why the renaissance has been as substantial as it is.
"The first reason is related to the biomechanical aspects of the procedure, with its reduced flap-related complications, sparing of corneal tissue, and reduced risk of post-LASEK ectasia, which is less than the risk associated with LASIK. In addition, there is less risk of diffuse lamellar keratitis, reduced surgery-induced higher-order aberrations, and the reduced incidence of associated dry eye symptoms."
Dr. Lackerbauer and colleagues conducted a study that included 25 eyes that were treated with epi-LASIK, and 50 eyes that were treated with LASEK using alcohol to remove the epithelium.
The mean age of patients in the epi-LASIK group was 32.2 years (range, 22 to 59 years); the mean spherical equivalent was –3.5 D (range –1.25 to –6.25 D). In the standard LASEK group, the age range and the mean age were the same as in the epi-LASIK group. The mean spherical equivalent was about –3.71 D (range –1.75 to –6.5 D). In both groups, astigmatism was below 1.5 D. No enhancements were needed in either group, according to Dr. Lackerbauer. He is a consultant at the Center for Refractive Therapy, University Eye Hospital Munich, Munich, Germany.
All epi-LASIK procedures were performed with a proprietary epikeratome (Amadeus II, Advanced Medical Optics). All procedures were performed using the Allegretto Wave Eye-Q 400Hz (Wavelight/Alcon Laboratories).
The corrected visual acuity 3 months after the procedure was greater than 1 Snellen line of vision better compared with the best spectacle-corrected visual acuity preoperatively in 81% of the eyes that were treated with epi-LASIK and 79% of the eyes treated with LASEK. The uncorrected visual acuity postoperatively exceeded the best corrected visual acuity preoperatively in 36% of the eyes treated with epi-LASIK and in 33% of the eyes treated with LASEK, Dr. Lackerbauer reported.
The spherical equivalent was between ±0.5 D in 93% and 88% of the epi-LASIK group and the LASEK group, respectively, and between ±1.0 D in 96% and 96%, respectively.
Dr. Lackerbauer said that the stability of the two procedures was poor during the first 3 postoperative months with 69% and 61%, respectively.
When the investigators compared the best-corrected visual acuity 3 months postoperatively with the best-corrected visual acuity preoperatively there was a visual improvement of one Snellen line in 82% in the epi-LASIK group and 76% in the LASEK group. There was no loss of Snellen vision in the epi-LASIK group compared with a loss in 8% of eyes in the LASEK group. Finally, there was an improvement of greater than one Snellen line in 18% and 16%, respectively.
"Regarding precision, stability, safety, and efficacy, epi-LASIK provides slightly better refractive outcomes 3 months postoperatively compared with standard LASEK. This may be due to the quicker and smoother separation of the epithelial layer from Bowman's membrane and the absence of alcohol with its negative effect on energy absorption of the excimer laser. This is perhaps the result of a short wound-healing period and a less intensive wound-healing reaction," Dr. Lackerbauer concluded.