LASIK Eye Surgery and Other Refractive Surgeries
Procedures Related to LASIK Surgery
Doctors have developed other surgeries similar to the standard LASIK procedure. These include the following.
Wavefront-guided LASIK uses a highly detailed "map" of how light moves through the eye to guide the laser treatment. This shows even the subtlest distortions of focus. The goal is to reduce the chance of after-surgery problems such as glare, light "halos," blurry vision, and poor night vision.
PRK (photorefractive keratectomy) corrects low to high nearsightedness, low to moderate farsightedness, and astigmatism. The eye surgeon removes the epithelium (surface cells on the cornea). The surgeon then uses the excimer laser to reshape the cornea. Healing occurs with help from a "bandage contact lens" applied at the end of the procedure. Initial healing occurs during the first week and may involve some discomfort. Full visual recovery may take weeks or months. For these reasons, LASIK surgery has generally replaced PRK, except for patients with corneas too thin for LASIK surgery or others with certain lifestyles or professions (such as professional athletes).
LASEK (laser epithelial keratomileusis) is very similar to PRK. The difference is that the surgeon removes and then replaces the epithelium after completing the surgery. Like PRK, LASEK may be recommended for people with thin corneas. As with PRK, healing may involve some discomfort.
Epi-LASIK uses a special instrument, the Epi-keratome, to create the corneal flap on the layer of cells covering the cornea (epithelium). Epi-LASIK is used primarily in patients who cannot have standard LASIK surgery.
Implant Refractive Surgery
Several types of refractive surgery rely on implants to improve vision. These procedures include the following:
- Intrastromal corneal ring segment (INTACS) implants
- Phakic intraocular lenses (IOLs)
- Accommodative IOLs, multifocal IOLs, toric (astigmatism correcting) IOLs aka refractive lens exchange or clear lens extraction
Each implant is described below.
Intrastromal corneal ring segment (INTACS) implants. Semicircular pieces of plastic are implanted in the cornea. These objects are called INTACS (intrastromal corneal ring segments). They change the cornea's shape and adjust the person's power to focus. INTACS are inserted through a small corneal incision. The incision is closed with two small sutures, or stitches, or with a special tissue glue. Stitches are typically removed two to four weeks later. If necessary, INTACS can be removed. The cornea returns to its original shape within a few weeks. These were introduced just prior to the emergence of LASIK as the dominant procedure to treat nearsightedness. LASIK and related procedures have replaced INTACS for refractive surgery. INTACS are now primarily used in the corneal degeneration called keratoconus.
Phakic IOLs. These are used for people whose degree of nearsightedness or farsightedness is too high for safe use of the excimer laser. The procedure is similar to cataract surgery except that the natural lens is not removed. The eye surgeon positions a vision-correcting plastic lens in front of the patient's natural lens. Because the eye is actually entered, phakic IOL surgery considered more invasive than LASIK. This has to be balanced against the benefits to people with extreme eyeglass or contact lens prescriptions who are not eligible for a laser procedure.
Accommodative IOLs, multifocal IOLs, toric (astigmatism correcting) and refractive lens exchange. These implants are used to treat nearsightedness, farsightedness, astigmatism, and presbyopia. Vision-correcting, surgically implanted artificial lenses replace the patient’s natural lenses. No corneal reshaping is done.