Astigmatism, is the term used to describe an irregular shape to the cornea. Instead of a symmetrical round shape, the cornea is shaped more like a football (more curved in one direction than the other).

This causes light to focus in more than one point on the retina, resulting in blurry and distorted vision. Astigmatism often occurs in combination with myopia (nearsightedness) or hyperopia (farsightedness).

Symptoms of Astigmatism

Blurry distorted vision at both near and far

Causes of Astigmatism

• Heredity

• Pressure on the eye from eyelid swellings, such as a stye (chalazia)

• Keratoconus and other corneal dystrophies

• Corneal scars from trauma or infections

Treatment

Glasses and contact lenses are used by many for the temporary treatment of astigmatism. Refractive procedures such as Lasik, Astigmatic Keratotomy, and Limbal Relaxing Incisions can permanently alleviate astigmatism. Toric Intraocular lenses can be used in conjunction with cataract surgery to also improve or alleviate astigmatism.

Your eye doctor can conduct a refractive evaluation to determine whether your eyes focus light rays exactly on the retina at distance and near. A visual acuity test will determine your ability to see sharply and clearly at all distances. Your eye doctor will also check your eye coordination and muscle control, as well as your eyes' ability to change focus. All of these are important factors in how your eyes see.

Surgical Correction of Astigmatism 

Astigmatism, which represents an uneven or asymmetrical corneal surface can be temporarily treated with glasses or contact lenses, or permanently treated surgically or with a laser ( see Lasik ).   Below, we will discuss the surgical treatment of astigmatism, which includes Limbal Relaxing Incisions ( LRI ), and Toric Intraocular Lenses.

Limbal Relaxing Incisions (LRI)
Limbal Relaxing Incisions are hairline incisions made in the peripheral cornea with a diamond blade. When placed in the steep axis of the cornea, astigmatism can be reduced or elimnated. LRI's are often performed at the same time cataract surgery to improve unaided vision.

Toric Intraocular Lenses

Toric IOLs are similar to standard or monofocal IOLs except like astigmatism correction in glasses, the lens provides for the reduction or elimination of astigmatism, which means the recipient will achieve better unaided  visual acuity. These lenses are always used in conjunction with cataract surgery, which is a short fifteen to twenty-minute procedure done under topical anesthesia. The eye is marked beforehand to determine the steep axis where the astigmatism is present. The lens is then implanted in the eye and special markings on the lens are used to align it along  the pre-marked steep axis. Studies have shown that when these lenses are used in both eyes, 97% of recipients will achieve freedom from glasses.