Astigmatism is when the eye has an oval rather than a round shape. Because of this, a person with astigmatism can’t wear normal contact lenses.
During a comprehensive eye exam, your eye doctor will conduct several tests to diagnose astigmatism. Eyeglasses and contact lenses are the most common forms of corrective treatment for astigmatism.
If you wear contact lenses and are diagnosed with astigmatism, you will need special contact lenses for this condition. We discuss astigmatism, its causes, and what kind of contact lenses work best.
What Is Astigmatism?
Ideally, the eyeball is shaped like a round ball which allows light to bend evenly, giving you clear vision. In astigmatism, the eyeball is like a football shape. This prevents light from focusing on the retina (the light-sensitive tissue at the back of the eye).
Astigmatism is a refractive error as light bends in more than one direction when it enters the eye, resulting in blurry or distorted vision. It’s common to have nearsightedness or farsightedness with astigmatism.
There are 2 types of astigmatism:
- Corneal astigmatism—a defect in the cornea (transparent front layer of your eye).
- Lenticular astigmatism—a defect in the lens (inner part of your eye).
Symptoms of Astigmatism
The symptoms of astigmatism can vary among individuals, but here are common symptoms:
- Blurred distant and near vision
- Eye strain
- Eye discomfort
- Eye irritation
- Squinting to see clearly
- Trouble seeing at night
Children may not realize they have blurry vision. And because these symptoms alone don’t always confirm astigmatism, eye exams can help determine the cause of your symptoms.
Risk Factors for Developing Astigmatism
Doctors aren’t sure why the cornea or lens shape varies in people. Some people are born with it, while others can develop it later as children or adults. The following factors can put you at risk for developing astigmatism:
- Family history of astigmatism or keratoconus
- Thinning or scarring of the cornea
- Excessive near or farsightedness
- Eye surgery, such as cataract surgery
- Eye injury
Treatment for Astigmatism
Corrective eyeglasses and contact lenses or surgery are used to treat astigmatism. Mild cases of astigmatism without vision problems usually don’t need correction.
Eyeglasses are curved to counteract the shape of the cornea or lens of your eye. Single-vision lenses can provide clear vision at varying distances. Eyeglasses for astigmatism also come in bifocal and progressive lenses.
If you prefer contact lenses and have astigmatism, standard contact lenses won’t work. Your eye doctor can prescribe toric and rigid gas-permeable contact lenses.
Soft toric contact lenses are comfortable and designed to prevent them from rotating when you blink. Getting the right fit of toric lenses is extremely important.
During a contact lens exam and fitting, your eye doctor takes measurements of your pupil and the cornea’s curvature to ensure comfort and clear vision.
Rigid gas permeable or hard lenses can provide a better option for severe astigmatism. Unlike soft toric lenses that conform to the eye’s surface, rigid gas-permeable lenses are rigid and retain their shape.
Your eye doctor may recommend you wear rigid gas-permeable lenses as your regular contact lenses or for orthokeratology. This is when you wear the lenses for some time, mainly overnight, to temporarily reshape the cornea and remove them during the day.
As the cornea’s curvature evens, you can reduce wear time to maintain the new shape. However, if you discontinue wearing the lenses, the eye returns to its former shape.
Scleral lenses are another rigid gas-permeable option for treating severe astigmatism. These special lenses are larger in diameter and cover the cornea and the sclera (white part of the eye).
Because of their large size, they are generally more comfortable, stable, and rarely dislocate, allowing for clearer vision. Scleral contact lenses don’t sit on the cornea like other contact lenses. They vault over the cornea with a tear reservoir beneath that provides hydration while correcting vision.
Hybrid lenses are a combination of soft and hard lenses. The center is made of rigid gas-permeable material, and the surrounding area is soft hydrogel or silicone hydrogel.
Hybrid lenses require more time and expertise when fitting compared to soft toric lenses since they are custom-made to fit the individual. They don’t need to be replaced as often as soft lenses and can provide comfort with a high level of clarity.
Refractive surgery such as LASIK and other procedures uses a laser to reshape the cornea to correct astigmatism.
Specialty Contacts for Astigmatism
For correcting astigmatism, there is no best way. Treatment depends on individual vision needs and lifestyle. Contact Total Vision La Mesa or book an appointment to discuss your treatment options for astigmatism.