Astigmatism is blurred vision caused by an uneven curve in your cornea. The cornea is the clear outer layer on the front of the eye. As a result of astigmatism, your vision is somewhat blurry all the time.
Astigmatism can be corrected with some kinds of contact lenses:
Toric lenses are usually thicker and heavier at the bottom. This keeps the lens in the correct position on the eye. Like regular lenses, toric lenses may be soft or gas permeable. Fitting toric contact lenses takes more time and expertise than regular contacts. Toric lenses are also usually more expensive.
Gas permeable (GP) contact lenses let oxygen reach the cornea. GP lenses may be called hard lenses because they are stiffer than soft contact lenses. They often correct vision better than soft lenses do, especially if your cornea is scarred or has an uneven shape.
Presbyopia contact lenses
Presbyopia is the natural loss of clear close-up vision as you get older. Around the age of 40, the lenses of your eyes start to be less flexible. This causes the eye to be unable to focus sharply on close objects. You may need to hold things farther away from your eyes to see them clearly.
People who wear contact lenses can wear contacts to see at a distance and a pair of reading glasses to see close objects. It is also possible to correct presbyopia with contacts.
With monovision, you wear a contact lens in one eye for seeing distances and a lens in the other eye for reading. Monovision takes time to get used to. Your brain must learn to “see” with one eye at a time, and you may have problems with depth perception. Monovision does not work for everyone.
There are several types of bifocal contact lenses:
Some have the distance power in the center of the lens and the reading power on the outside, or the reading power on the inside and the distance power on the outside.
Some have the distance power on the top and the reading power on the bottom, like bifocal glasses. These lenses are usually weighted so that the reading power stays on the bottom when you wear them.
Some lenses blend near and distance powers from the outside to the center of the lens.
You may adjust quickly to bifocal contacts, but you may have some problems. You may feel that your vision is not as clear as you are used to, or it may change when the lens moves on your eye. You may see images that seem to jump when you change from distance to close-up vision, a three-dimensional effect or ghost image when you read, or a halo around lights. Problems like these can sometimes be corrected with a change in lenses. Sometimes the problems may get better as you get used to the new lenses.
If problems continue with lenses, presbyopia can also be corrected with bifocal glasses. Bifocals have the distance prescription on the top and the reading prescription on the bottom.
How do I choose the right type?
You may need to try several different types of lenses. Contacts come as soft lenses and gas permeable (GP) lenses. Your eye care provider can recommend which type you should try, and trial lenses can be ordered.
Choosing which type of contact lens is best for you is based on:
Your age and eyeglass prescription
The type of work you do
The way you use your eyes (for example, if you look straight ahead to read rather than looking down)
The shape of your eye
The size of your pupils
What precautions should I take with contact lenses?
When you first start wearing contacts, carefully follow the break-in schedule prescribed by your eye care provider.
Wash your hands with soap and water before you put in or take out your contacts.
Do not wear your contacts while swimming. Soft lenses absorb chemicals from the water. Gas permeable lenses can float out of your eyes.
Donâ€™t wear your lenses for longer than recommended. Follow your eye care provider’s instructions about how long you can safely keep the lenses in your eyes. Do not sleep in your contact lenses unless your provider tells you that itâ€™s okay to do so.
Always put your contacts in your eyes before you put makeup on. Use water-soluble makeup. Do not use lash-building mascara, because particles may get into your eyes. If you put eyeliner between your lashes and your eyes, you may discolor soft lenses permanently.
Use aerosol sprays, such as deodorant and hair spray, before you put in your lenses.
If you have medical problems, note on your Medic Alert bracelet or card that you wear contact lenses.
Do not put contact lenses in your mouth to moisten or clean them. It may increase your risk of eye infection.
Do not use eyedrops without your eye care providerâ€™s approval. The lens can absorb the eyedrop solution and result in a buildup. This could cause an infection or damage the lens.
If you have burning, redness, pain, unusual light sensitivity, or blurry vision, remove your contacts and see your eye care provider right away.
Adult Advisor 2015.1 published by RelayHealth. Last modified: 2013-12-09 Last reviewed: 2014-10-27
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
Contact Lens: Types of Vision Correction: References
American Academy of Ophthalmology. 2013-2014 Basic and Clinical Science Course. San Francisco: American Academy of Ophthalmology, 2013; v.1-13.
Krachmer JH, Mannis MJ and Holland EJ, eds. Cornea, 3rd edition. Philadelphia: Mosby, 2010;v.1-2.
Yanoff M and Duker JS. Ophthalmology, 4th edition. Philadelphia: Mosby, 2013.