Keratotomy Techniques
These include:
Flap procedures
Consists in cutting a flap in the cornea in order to access the tissue underneath.
Its is a surgical procedure used to correct vision in people with severe nearsightedness and mild degrees of farsightedness. ALK is no longer routinely performed due to more predictable results from other vision correction procedures.
- Laser Assisted In-Situ Keratomileusis LASIK is the most commonly performed refractive surgery procedure as of 2007. Surface treatment ablation has gained a renewed interest in recent years as evidence of good outcomes have been shown.LASIK is performed for a wide range of nearsightedness. The surgeon uses an instrument called a microkeratome to cut a flap of the corneal tissue (usually with about 160 micra in thickness). He then opens the flap like a hinged door, removes the targeted tissue in the corneal stroma beneath it with the excimer laser, and then replaces the flap. Some variations do not use a microkeratome but cut the flap with a laser (intralase).
- Laser Assisted Sub-Epithelium Keratomileusis (LASEK) is a procedure that changes the shape of the cornea using an excimer laser to ablate the tissue from the corneal stroma, under the corneal epithelium, which is kept almost intact to act as a natural bandage.
- EPI-LASIK is a new technique similar to LASEK, that uses an epi-keratome (rather than a trephine blade and alcohol) to remove the top layer of the cornea.
- Corneal implants,Plastic corneal rings, called Intacs.
Photoablation procedures
- PhotoRefractiveKerectomy (PRK) is an outpatient procedure generally performed with local anesthetic eye drops (as LASIK . It is a type of refractive surgery which reshapes the cornea by destroying microscopic amounts of tissue from corneal stroma, using the computer-controlled beam of light (an excimer laser). The difference from LASIK is that all the epithelium is removed (and a bandage contact lens must be used). Recovery time is much longer with PRK than with LASIK, though the final outcome (after 3 months) is about the same (very good). More recently, customized ablation have been performed either with LASIK or PRK.
Corneal incision procedures
- Radial Keratotomy (RK) uses spoke-shaped incisions (usually made with a diamond knife) to alter the shape of the cornea and reduce myopia or astigmatism; this technique has now been largely replaced by the other methods (that use excimer laser).
- Arcuate keratotomy (AK) is similar to radial keratotomy, but the incisions on the cornea are done at the periphery of the cornea. Arcuate keratotomy is used to correct astigmatism. Although most incisional procedures are replaced nowadays by LASIK, (AK) is still used in some special cases (correction of residual astigmatism after a keratoplasty procedure or during cataract surgery).
