Refractive surgery is eye surgery that is designed and performed to reduce or eliminate refractive errors of the eye – nearsightedness, farsightedness and astigmatism.
Refractive surgery can also “correct” presbyopia (the normal age-related loss of near focusing ability) by eliminating the refractive error of one eye and intentionally making the other eye mildly nearsighted. This is called monovision – one eye sees distant objects clearly and the other eye sees near objects clearly. With both eyes open, vision is clear and comfortable at all distances.
There are several types of refractive surgery, including:
LASIK (Laser-Assisted In Situ Keratomileusis)
This laser procedure involves creating a thin flap on the cornea (with a laser or a microkeratome) and reshaping the underlying corneal tissue with a laser.
PRK (Photorefractive Keratectomy)
This laser procedure is similar to LASIK, but the laser treatment is performed on the surface of the cornea, not under a corneal flap.
LASEK (Laser Epithelial Keratomileusis)
LASEK is a laser procedure that can be considered something between LASIK and PRK. A corneal flap is created in LASEK, but it is significantly thinner than a LASIK flap and consists of only the top layer of corneal cells (called the epithelium). LASEK is also called Epi-LASIK.
RLE (Refractive Lens Exchange)
CLE (Clear Lens Extraction)
This is an intraocular (inside the eye) procedure in which the normal crystalline lens of the eye is removed and replaced with an artificial lens. Measurements are taken prior to surgery to determine the correct power of the artificial lens (or lens implant) for perfect vision. RLE can correct higher amounts of nearsightedness and farsightedness than LASIK and other refractive surgery procedures. Refractive Lens Exchange is also called Clear Lens Extraction (CLE).
ICL (Implantable Contact Lenses)
In this intraocular procedure, a contact lens is implanted inside the eye. The lens is attached to the front of the iris or positioned directly behind it. ICL (like refractive lens exchange) can correct higher amounts of nearsightedness and farsightedness than LASIK and other refractive surgery procedures. The ICL procedure is also called Phakic IOL surgery. (Phakic means the natural lens remains in the eye; IOL is an abbreviation for intraocular lens.)
ICRS (Intrastromal Corneal Ring Segments)
This procedure involves inserting clear plastic rings within the peripheral corneal tissue to flatten the central cornea and correct mild amounts of nearsightedness. This procedure has also been approved to correct keratoconus (a disease of the cornea that causes distorted vision). The trade name for ICRS is Intacs(R).
LTK (Laser Thermal Keratoplasty)
This procedure involves the use of heat from a thermal laser to create a ring of laser spots in the peripheral cornea. These spots tighten the peripheral corneal tissue and steepen the central cornea to correct mild amounts of farsightedness. LTK is also used to “correct” presbyopia with monovision.
CK (Conductive Keratoplasty)
CK is similar to LTK, but uses heat from radio frequency waves emitted by a hand-held surgical tool to change the shape of the cornea. Like LTK, conductive keratoplasty can correct mild amounts of farsightedness and create a monovision condition to “correct” presbyopia.
RK (Radial Keratotomy)
This is a non-laser surgery in which radially-arranged incisions are made in the cornea. The healing of these cuts flattens the central cornea to correct nearsightedness. RK is the original refractive surgery procedure. But since the introduction of laser procedures, it is no longer considered the standard of care.
AK (Astigmatic Keratotomy)
This non-laser procedure is similar to RK, but incisions are made in only one or two quadrants of the cornea to make it more symmetrical in shape and thereby correct astigmatism.
Refractive surgery is performed only by medical eye doctors (ophthalmologists). If you are interested in reducing or eliminating your need for eyeglasses and contact lenses, visit your eye doctor to see if you are good candidate for refractive surgery and to determine which procedure is best for you.