Corneal Relaxing Incisions

Normally, the front surface of the eye (the cornea) is shaped like a sphere (basketball). This permits light to focus in one distinct point, which is necessary for clear vision. When the cornea is oval, or shaped like a football, a condition known as astigmatism is present. Astigmatism causes light to focus in more than one point, resulting in blurred vision.

Correcting astigmatism

Astigmatism is corrected with glasses or contact lenses, but can be permanently corrected surgically. Corneal relaxing incisions (otherwise known as limbal relaxing incisions or astigmatic keratotomy) placed on the steep axis of the cornea can reduce or eliminate astigmatism, thereby reducing the eye´s dependency upon glasses or contact lenses. Corneal relaxing incisions are, therefore, a type of refractive surgery.

Corneal relaxing incisions can be performed alone, but are sometimes combined with cataract surgery to lessen the eye´s dependency upon corrective lenses. The actual incisions differ in number, position, and in length depending upon the degree and position of the astigmatism. Preoperative measurements used to analyze astigmatism to plan its correction include keratometry and corneal topography.

Astigmatism can also be corrected by Laser Vision Correction (Lasik or PRK). While generally more accurate than limbal relaxing incisions, Laser Vision Correction is generally more expensive.