LASEK is not a misspelling of LASIK, but a minor modification of the PRK procedure, which was the first laser procedure to be approved by the FDA in 1995. PRK and LASEK use the same lasers, the same computers, and reshape the cornea in the same way as the LASIK procedure. The main difference is that in PRK/LASEK there is no corneal flap. Although the healing takes longer for PRK/LASEK than for LASIK, the visual results are the same.
In PRK, the surface cells (epithelium) of the cornea are polished and removed. In LASEK these cells are loosened with alcohol, laid out of the way in a sheet (not a LASIK flap) and then used to recover the corneal surface after the laser has been applied to the surface of the cornea. EPI-LASIK is essentially the same procedure as LASEK (not LASIK), but the epithelial “sheet” is created using a special modification of the microkeratome generally used to make the (deeper) LASIK flap. The advantage of the EPI-LASIK over LASEK is that no alcohol is used to create the epithelial sheet. This results in more rapid recovery. In PRK, LASEK or EPI-LASIK, a bandage contact lens is placed on the eye for about one week as the surface cells heal.
PRK, LASEK or EPI-LASIK are known as “surface procedures”. They are performed for patients who are not good candidates for the LASIK procedure and for the occasional patient who would otherwise be a good candidate for LASIK, but requests PRK, LASEK or EPI-LASIK. The main indication for the PRK, LASEK or EPI-LASIK procedure is a cornea which is too thin to safely undergo a LASIK flap, or a cornea with relatively normal thickness but has a mildly abnormal configuration such that it may not be safe to perform LASIK. Additionally, for some patients in high risk occupations or with high risk hobbies where they are likely to incur a physical eye injury with potential damage to the flap, PRK, LASEK or EPI-LASIK may be preferable.
For the PRK, LASEK or EPI-LASIK procedures the excimer laser is programmed the same as for the LASIK procedure, but because the laser is applied directly to the surface of the cornea, there can be no flap complications such as microfolds, or intra-operative or post-operative flap trauma. The disadvantage of the PRK, LASEK or EPI-LASIK procedures is that it may take up to 3 weeks for vision to become clear. Therefore, unlike LASIK, most patients elect to have PRK, LASEK or EPI-LASIK in one eye at a time. A corrective contact lens is worn in the unoperated eye until the vision is clear enough in the operated eye and then the second eye undergoes surgery. This is typically 3 to 4 weeks after the first eye. If a patient does not wear contact lenses, then the unoperated eye can be corrected with a spectacle lens while clear glass can be placed in the spectacle over the operated eye during the healing process.
Most of the risks and complications of the PRK, LASEK or EPI-LASIK procedures are the same as for the LASIK procedure. Therefore, patients must view my video/DVD on LASIK prior to undergoing PRK, LASEK or EPI-LASIK. The additional complication that can occur following PRK, LASEK or EPI-LASIK, but not in LASIK patients, is the potential for scarring on the surface of the cornea. This scarring, if left untreated, can significantly decrease visual acuity as well as the quality of the vision and may induce regression back towards nearsightedness and/or astigmatism.
In order to diminish the possibility of scarring in the higher myope (-6.00 diopters and above), since 1999, I have been performing PRK, LASEK or EPI-LASIK with the intra-operative use of Mitomycin-C. Although not FDA approved for this procedure, it is common and standard practice among experienced refractive surgeons. Mitomycin-C is a cancer chemotherapeutic agent which, in this case, is used to prevent scarring of the surface of the cornea following PRK, LASEK or EPI-LASIK. In every case that I have used Mitomycin-C, no scarring has occurred. I have not observed nor am I aware of any complications that result from the off-label use of intra-operative Mitomycin-C in the concentrations and for the time periods for which we use it in refractive surgery.
Like all corneal refractive procedures, following PRK, LASEK or EPI-LASIK, a certain percentage of patients require an enhancement for overcorrection, undercorrection, or induced astigmatism. Your probability of needing an enhancement is based on many factors such as your degree of nearsightedness, farsightedness and/or astigmatism, as well as individual healing factors which cannot be predicted. If you require an enhancement, this is usually performed 6 to 8 months after your initial procedure to ensure that the refraction is stable. If an enhancement is required, a repeat PRK or LASEK oftentimes with Mitomycin-C will be performed.