A patient from Oxnard asked me about the differences between Customized Wavefront LASIK and PRK. The goal of either LASIK or PRK is to use the excimer laser to reshape the cornea to allow it to focus precisely. Customized Wavefront LASIK involves first creating a thin surface flap, lifting it, and then applying the wavefront guided laser to shape the underlying cornea. The flap is then re-positioned and conforms to the new shape sculpted by the laser beam. PRK sometimes is called “flapless LASIK.” Customized Wavefront PRK is essentially the identical procedure to Customized Wavefront LASIK, but no flap is created. Rather than creating the flap, the very thin skin layer covering the cornea is painlessly removed, the same wavefront guided laser is applied to the surface of the cornea, and then the skin layer is allowed to grow back over the newly shaped corneal surface. Each approach has its pros and cons. The main benefit of the LASIK flap for most patients is very quick recovery. PRK has slower recovery, but leaves the integrity of the cornea more intact and does not have the biomechanical impact on the cornea that LASIK does. However, as a trade off, visual recovery clearly is slower than with LASIK. A new study from Stanford University was published today in the Journal of Cataract and Refractive Surgery that helps clarify the difference in recovery rates. This study of 34 patients was a “contralateral eye” study in which one eye had Customized Wavefront LASIK and the other eye of the same patient had Customized Wavefront PRK. Patients were examined at 1 day, 1 week, 1 month, 3 months, 6 months, and 12 months after surgery. The benefit of a contralateral eye study is that it minimizes genetic factors since LASIK is compared to PRK in the same patient. In this study, as in most previous studies, the LASIK eye clearly healed faster and produced better vision for the first month. By three months, however, there were no differences in visual results. This study confirms that ultimately outcomes are the same whether or not a flap is created. The flap simply allows for faster visual recovery. The quality of the final result, however, is determined by the quality of the laser beam which was the same for both the Customized Wavefront LASIK and the Customized Wavefront PRK eyes in this study. Stanford University used a VISX S4 IR wavefront guided laser in their study, which is the laser I also prefer and use in my own practice. This study is consistent with previous studies, including military studies, which have demonstrated ultimately equal visual outcomes with LASIK and PRK and is consistent with studies I have presented at teaching conferences and with what I observe on a daily basis in my own practice.