The best types of contact lenses for people with minor astigmatism are regular soft, disposable contact lenses which don't have any correction for astigmatism. More moderate levels of astigmatism often are remedied with a specially shaped contact lens called toric lenses.
Although some mild cases of astigmatism may not need treatment, a majority of people with astigmatism will need toric contact lenses.
“For astigmatism treatment at the time of cataract surgery, use toric IOLs whenever you can—roughly speaking, for with-the-rule astigmatism greater than 1.5 D and against-the-rule greater than 0.4 D,” recommends Dr. Raviv.
If a patient has -0.75 or more of astigmatism, they will see better with a toric contact lens. Even relatively low amounts of astigmatism can lead to reductions in visual performance. The impact of astigmatic blur upon vision depends upon the axis of the astigmatism.
We recommend speaking with your optometrist to determine the most appropriate lens options for your vision. Now for the good news – Patients with astigmatism are no longer limited to eyeglasses or rigid contact lenses for vision correction!
Q: Can you wear regular contact lenses if you have astigmatism? A: No, if you have astigmatism, it's essential that you wear specialized contact lenses because your condition can worsen if not. Regular contact lenses do not cover your cornea's entirety, which will impair your ability to see even further.
People with mild astigmatism might be able to wear normal contact lenses, but you'll typically need specialty lenses if your astigmatism is more severe. Even with astigmatism, you're not out of options.
75 and 2 diopters is considered mild astigmatism. Between 2 and 4 diopters is moderate astigmatism, and 4 or more diopters is considered significant or “bad” astigmatism. Generally, eyes with 1.5 diopters of astigmatism or more require correction.
Astigmatism is measured in diopters. A perfect eye with no astigmatism has 0 diopters. Most people have between 0.5 to 0.75 diopters of astigmatism. People with a measurement of 1.5 or more typically need contacts or eyeglasses to have clear vision.
The basic rule is that if the lens rotates clockwise the degree of rotation should be added to the axis, but if it rotates anti-clockwise the rotation should be subtracted from the axis (CAAS).
Pro: Toric lenses generally provide clear distance vision. For some people, toric lenses give them the crispest vision of their life. Con: You will likely need glasses or contact lenses to read. Also, you will likely have to pay an extra fee for either a toric IOL or an LRI.
Mild astigmatism (less than 1.00 diopter) – Mild astigmatism is considered normal, and individuals who have it often don't need corrective lenses or surgery to see clearly. Moderate astigmatism (1.00 to 2.00 diopters) – The symptoms of moderate astigmatism are already noticeable.
Patient Selection
The patient should have visually significant cataract and astigmatism. A good candidate will be interested in spectacle independence even if only for one focal point (usually distance).
Our eye doctors advise against it, as regular contacts won't cover your cornea fully, leaving areas of your vision unprotected. Instead of choosing generic contacts, talk to your eye doctor about the types of toric lenses.
If you have astigmatism, light that enters your eye is bent more than it should be. The light can't properly focus on your retina. This means only parts of an object you're looking at are in focus. That uneven focus makes objects look blurry or wavy.
For many people, toric astigmatism-correcting IOLs are worth it. The right lenses for you will depend on the refractive error you are aiming to correct. Since they can offer many people better vision after cataract surgery, they are often worth their increased price.
Astigmatism Severity Scale
For context, a perfect eye that has no astigmatism has 0 diopters, but some people have between 0.5 and 0.75 diopters of astigmatism. People who have about 1.5 or more diopters of astigmatism usually opt to have corrective treatment such as glasses, contacts, or eye surgery.
What Level of Astigmatism Requires Glasses? You'll likely need glasses if your astigmatism has a strength of 1.0 or more. But even if your astigmatism needs less than 1.0 diopters of correction, it doesn't mean you won't need glasses.
When you get your eyes tested for glasses, you are able to detect 1/4 (0.25) Diopter of astigmatism. Some people can detect even less. Small amounts of astigmatism, up to 0.50 Diopter, probably will not bother you during your normal activities. Vision becomes noticeably blurry with 1.00 Diopter of astigmatism or more.
CONCLUSIONS: In most subjects, astigmatism less than 0.5 D did not degrade visual acuity. This suggests that under clinical conditions, the visual benefit of precise correction of astigmatism less than 0.5 D would be limited.
If left untreated, astigmatism may cause eyestrain, headaches, and blurry vision. If you have astigmatism you may not see objects in the distance or near without some form of distortion.
Will astigmatism get worse if my glasses prescription is wrong? Wearing glasses can't make astigmatism worse, even if they are the wrong prescription. Astigmatism is caused by the shape of the eye's cornea or lens, and glasses can't change those.
Due to the irregular curvature of the corneas, people with astigmatism cannot use traditional spherical soft contact lenses to correct their vision, as contact lenses tend to rotate slightly with each blink. Spherical lenses on astigmatic eyes would thus shift in an out of focus each time the user blinks.
Toric contact lenses can rectify astigmatism. The main difference between these and regular lenses is the design. Regular lenses have just one power, but toric lenses have two: one for distance vision and one for astigmatism.
It generally takes more expertise for an eye doctor to fit a patient for toric contacts than it does for regular lenses. For this reason, a toric lens fitting may cost more than a regular contact lens fitting. Since torics are more complex in design, the cost of replacing them will be higher than most regular contacts.