Astigmatism

What is astigmatism?

Astigmatism is a common eye condition marked by an irregular curvature of the cornea. This type of condition is also known as a refractive error, and occurs in nearly everyone to some degree. If the cornea is significantly curved, the condition must be treated.

A person's eye is naturally spherical in shape. Under normal circumstances, when light enters the eye, it refracts evenly, creating a clear view of the object. However, the eye of a person with astigmatism is shaped more like a football or the back of a spoon. For this person, when light enters the eye, it is refracted more in one direction than the other, allowing only part of the object to be in focus at one time. Objects at any distance can appear blurry and wavy.

What causes astigmatism?

Astigmatism can be hereditary and is often present at birth. It can also be the result of pressure from the eyelids on the cornea.

What are the symptoms of astigmatism?

People with undetected astigmatism often experience headaches, fatigue, eyestrain and blurred vision at all distances. While these symptoms may not necessarily be the result of astigmatism, you should schedule an eye exam if you are experiencing one or more symptoms.

How is astigmatism diagnosed?

Astigmatism can only be diagnosed with a thorough eye exam by your optometrist or ophthalmologist. Astigmatism may occur with other refractive errors such as myopia (nearsightedness) and hyperopia (farsightedness). Unfortunately, astigmatism sometimes goes undetected in school-age children.

Because astigmatisms may increase slowly, you should visit your optometrist or ophthalmologist for an eye exam once a year. Optometrists are trained specifically to determine and improve visual acuity with the prescription of eyeglasses or contact lenses. Ophthalmologists can provide total eye care, from examinations and vision correction to the diagnosis and treatment of disease through medication and surgery.

How is astigmatism treated?

Almost all degrees of astigmatism can be corrected with properly prescribed glasses or lenses. For a person with only a slight degree of astigmatism, corrective lenses may not be needed at all, as long as other conditions such as nearsightedness or farsightedness are not present. If the astigmatism is moderate to high, however, corrective lenses are probably needed.

For moderate to high astigmatism, special corrective lenses called toric lenses are prescribed. Toric lenses have greater light-bending power in one direction than the other. After performing various tests, your eye doctor will determine the ideal toric lens prescription for your astigmatism.

Another method for correcting astigmatism is by changing the shape of the cornea through refractive surgery. While there is more than one type of refractive surgery, specific treatments are recommended on an individual basis.

Refractive surgeries require generally healthy eyes. As technology progresses, it is important that you explore all options and possibilities with a qualified refractive surgery specialist before deciding which refractive surgery and treatment is right for you.