Limbal Relaxing Incisions (LRI) are a refractive surgical procedure

Refractive surgery

Refractive eye surgery is any eye surgery used to improve the refractive state of the eye and decrease or eliminate dependency on glasses or contact lenses. This can include various methods of surgical remodeling of the cornea or cataract surgery. The most common methods today use excimer lasers to...

 to correct minor astigmatism

Astigmatism

An optical system with astigmatism is one where rays that propagate in two perpendicular planes have different foci. If an optical system with astigmatism is used to form an image of a cross, the vertical and horizontal lines will be in sharp focus at two different distances...

 in the eye. Incisions are made at the opposite edges of the cornea

Cornea

The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Together with the lens, the cornea refracts light, with the cornea accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is...

, following the curve of the iris

Iris (anatomy)

The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...

, causing a slight flattening in that direction. Because the incisions are outside of the field of view, they do not cause glare and other visual effects that result from other corneal surgeries like Radial Keratotomy

Radial keratotomy

Radial keratotomy is a refractive surgical procedure to correct myopia.- Discovery :The procedure was discovered by Svyatoslav Fyodorov who removed glass from the eye of one of his patients who had been in an accident. A boy, who wore eyeglasses, fell off his bicycle and his glasses shattered on...

.

LRI have become the most common technique to correct astigmatism as part of cataract

Cataract

A cataract is a clouding that develops in the crystalline lens of the eye or in its envelope, varying in degree from slight to complete opacity and obstructing the passage of light...

 surgery. They are simpler and less expensive than laser surgery such as LASIK

LASIK

LASIK or Lasik , commonly referred to simply as laser eye surgery, is a type of refractive surgery for correcting myopia, hyperopia, and astigmatism...

 or photorefractive keratectomy

Photorefractive keratectomy

Photorefractive keratectomy and Laser-Assisted Sub-Epithelial Keratectomy are laser eye surgery procedures intended to correct a person's vision, reducing dependency on glasses or contact lenses. The first PRK procedure was performed in 1987 by Dr. Theo Seiler, then at the Free University...

. Good results do not require the location and length of the incisions to be highly precise. And the incisions can easily be extended later if the original procedure did not correct all of the astigmatism.

Recovery is generally quick and painless, although the patient may experience discomfort.

External links

• http://www.medcompare.com/spotlight.asp?spotlightid=282
• http://www.stlukeseye.com/professionals/lri_nomogram.htm