Enhancement Surgery Flap
and Lasik, Bladeless Lasik, Epi-Lasik

During initial conventional or custom wavefront Lasik, and Bladeless Lasik, a flap of corneal stromal tissue is created. The excimer laser energy is applied under this flap to remove tissue and effect a change in refractive error. Lasik flaps are made with a mechanical microkeratome using a metal blade. Bladeless Lasik flaps are made with a femtosecond laser.

If enhancement surgery is required, it is almost universally preferred to lift the existing flap. Flaps made with a mechanical microkeratome have been lifted as much as 12 years after surgery. "Lifted" is probably not the correct term for a flap after this amount of healing time. It is more like separating the cornea at the location of the original flap.

The Bladeless Lasik flap tends to heal tighter at the edges. This makes it more difficult for the doctor to start the flap lift, however once started, the Bladeless Lasik flap can be lifted as well as a flap made with a mechanical microkeratome.

On rare occasion it is necessary to create a new flap. This is usually because the original flap is too thin or is otherwise less than perfect. To be able to create a second flap, the incision must be made significantly under or over the previous flap. If the new flap dissects through the first flap, irregular astigmatism and poor vision quality is likely to occur.

A flap made during Epi-Lasik consists only of epithelium. Although the epithelial flap will be repositioned after the laser energy is applied, it is not possible to have a second Epi-Lasik flap created because to create the Epi-Lasik flap with the special epikeratome, the Bowman's layer must be intact. The laser ablation during the initial surgery will have removed the Bowman's layer. If an epithelial flap is desired, only LASEK would be appropriate. PRK could be used, however the epithelium is not saved during PRK and saving the epithelium may be necessary for other reasons. Lasik and Bladeless Lasik can be performed after successful Epi-Lasik, using a stromal flap.