What is Astigmatism?
Astigmatism is a condition in which the eye does not focus light evenly, leading to blurry or distorted vision. Those with astigmatism have an irregularly shaped cornea. A normal cornea is rounded like a basketball. A cornea with astigmatism is usually flatter on one side and more curved on the other similar to the shape of a football. Most people with astigmatism are also nearsighted (have difficulty seeing objects far away clearly) or farsighted (have difficulty seeing objects close up clearly). Both children and adults can have astigmatism and it can occur in one or both eyes.
Symptoms of Astigmatism
Depending on the severity of the astigmatism, people may experience:
- Blurry or distorted vision
- Headaches
- Eyestrain
- Frequent squinting
How is Astigmatism Diagnosed?
Astigmatism is typically uncovered during a comprehensive eye exam. The optometrist will perform a variety of tests to see how the eyes focus light. Typically, the optometrist will test your visual acuity in which you will be asked to read a letter chart at a distance to test the clarity of your vision. He/she will also perform a refraction, which is a procedure to measure one’s potential prescription through the use of several lenses and tests. In some cases the optometrist may use instruments such as a keratometer or a corneal topographer. These instruments utilize light to map out the curvature of the cornea. With this information, and other tests, the optometrist can determine the correct prescription or course of treatment to correct your vision.
How is Astigmatism Treated?
There are four treatment options for astigmatism:
- Eyeglasses – Glasses can be created with a special lens prescription to compensate for your astigmatism and other visual deficits such as nearsightedness or farsightedness.
- Contacts – Contacts can provide better results for some people with astigmatism because they may allow for a wider field of view and clearer vision. They may also be a good option for individuals who have occupations in which wearing glasses doesn’t work well, or simply for cosmetic purposes.
- Orthokeratology (Ortho-K) – Ortho-K aims to temporarily correct the curvature and shape of the cornea. An individual wears special, gas-permeable contact lenses, which hold their shape, but allow oxygen to flow through the lens. Typically, they are worn overnight and removed in the morning. Ortho-K does not permanently correct vision; if one stops wearing the lenses as directed, the cornea will assume its original shape and visual capacity.
- Laser and other surgical methods – LASIK surgery uses a laser to remove tissue from the inner layer of the cornea. It permanently reshapes the cornea to provide clearer vision. Other laser surgery methods also focus on reshaping the cornea. Surgeries are performed by ophthalmologists.
An optometrist can discuss your available options and develop a customized treatment plan for your astigmatism.
To schedule a comprehensive eye exam, please contact The Eye Institute.