Astigmatism is a very common eye problem in which the cornea or lens is slightly misshapen, resulting in blurred or distorted vision. Most astigmatism is mild and can be easily compensated with the help of glasses or contact lenses. However, severe astigmatism can cause serious vision problems, chronic headaches, and other symptoms that make it difficult to perform basic daily tasks. Symptoms tend to worsen with age, and permanent blindness is a possible consequence of not receiving treatment. In most cases, severe astigmatism requires laser-guided eye surgery to correct the shape and curvature of the cornea.
In a healthy eye, the cornea and lens are evenly curved so that light gathered from any angle can be properly refracted on the retina. Severe astigmatism can cause a part of the lens or cornea to curve much more sharply than the surrounding area. The cornea can also be rough in the sense that bumps and steep ridges cover its surface. As a result, light hitting the cornea from certain angles is distorted when it hits the retina.
Most cases of astigmatism are hereditary and congenital. However, vision may not become a problem until a person reaches adolescence or adulthood. Natural changes in the eye tend to worsen astigmatism in older patients. Occasionally, a person may develop severe astigmatism after a puncture injury to the eye, surgery to correct glaucoma, or a serious viral or bacterial illness.
Severe astigmatism can affect both central and peripheral vision. Lack of definition can make it difficult or impossible to focus on text or an object. Severe astigmatism is often accompanied by significant nearsightedness or farsightedness, exacerbating vision difficulties. In addition to vision problems, a person may experience frequent headaches, fatigue, nausea, and dizziness.
An ophthalmologist can diagnose astigmatism by asking about your symptoms and doing a careful physical exam. A slit-lamp microscope is used to view the cornea from different angles. The doctor can determine exactly where the sharp ridges or curves are present and the degree to which they deviate from normal. Prescription glasses and rigid contacts can help some people with severe astigmatism achieve better vision, but most people eventually need surgery.
Laser-assisted in situ keratomileusis (LASIK) surgery is the most common procedure used to treat severe astigmatism. During the procedure, small slits are made in the cornea and held open while a laser burns off parts of the cornea and lens. The eye is shaped with the laser until it is smooth and evenly curved. Within a week of LASIK, a patient typically notices marked improvements in vision clarity and other symptoms of astigmatism.