Contact Lenses

Reviewed by Karen S. DeLoss, O.D.

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What Are Contact Lenses?

Contact lenses are medical devices worn directly on the cornea of the eye. Like eyeglasses, contact lenses help to correct refractive errors and perform this function by adding or subtracting focusing power to the eye's cornea and lens. Contacts provide a safe and effective way to correct vision when used with care and proper supervision. They can offer a good alternative to eyeglasses, depending on your eyes and your lifestyle. Over 24 million people in the United States now wear contact lenses. For certain conditions, contact lenses may be considered medically necessary.

Cosmetic contact lenses are used to correct the same conditions that eyeglasses correct:

  • Myopia (nearsightedness)
  • Hyperopia (farsightedness)
  • Astigmatism (distorted vision)
  • Presbyopia (need for bifocals)

The health of your eyes should be your main concern. Choose an optometrist who is knowledgeable and experienced with contact lenses.

It is recommended that all patients have a back-up pair of eyeglasses.

Types of Contact Lenses

Many types of contact lenses are available. The type of contacts you use depends on your particular situation. Your optometrist will be able to help you choose from the following types of lenses.

  • Soft contact lenses
    These are the most common type of contact lenses currently prescribed. These lenses are made materials that incorporate water, which makes them soft and flexible and allows oxygen to reach the cornea.
    • Daily disposable lenses: Although generally more expensive, they carry a lower infection risk
    • Two week or monthly disposable lenses: for daily wear
    • Toric contact lenses: Correct moderate astigmatism
    • Bifocal contact lenses: can be helpful for patients that need reading and distance correction but may not be right for everyone
  • Gas-permeable lenses
    These lenses are also known as "RGPs." They are rigid or "hard" lenses made of plastics combined with other materials—such as silicone and fluoropolymers—that allow oxygen in the air to pass directly through the lens. For this reason, they are called "gas permeable."

For the safety of your eyes, it is recommended that contacts should be removed at bedtime due to risk of infection and risk of contact lens intolerance.

Risk Factors

  • Daily-wear lenses should never be worn as extended-wear lenses. Misuse can lead to temporary and potentially sight threatening damage to the cornea. People who wear any type of lens overnight have a greater chance of developing infections of the cornea. These infections are often due to poor cleaning and lens care. Improper over wearing of contact lenses can result in intolerance, leading to the inability to wear contact lenses.
  • Gas permeable lenses can potentially scratch the cornea if the lens does not fit properly or if the lens is worn while sleeping. They are also more likely to slide off the cornea and become hidden under the lid.
    • Gas permeable lenses traditionally had a reputation for "popping out" of the eye. Newer lens designs have minimized the chance of losing a contact even during vigorous exercise.
    • Gas-permeable lenses and soft extended-wear contacts are the most likely to have protein build-up and cause lens-related allergies. Protein build-up results in discomfort, blurring, and intolerance to the lenses. Thus, nightly disinfection becomes imperative and  you mayneed special cleaning solutions to dissolve the protein.
  • Rigid gas-permeable or disposable lenses may be good choices for someone with allergies.

Who Should NOT Wear Contact Lenses?

Most people who need vision correction can wear contact lenses. Among the conditions that might keep you from wearing contact lenses are:

  • Frequent eye infections
  • Severe allergies
  • Dry eye (improper tear film)*
  • A work environment that is very dusty or dirty
  • Inability to handle and care for the lenses properly

Are Contacts for You?

Whether or not contact lenses are a good choice for you depends on:

  • Individual needs and expectations
  • Patience and motivation during the initial adjustment period to contact lens wear.
  • Adhering to contact lens guidelines for wear, disinfecting, and cleaning
  • Diagnosis and treatment of conditions that may prevent contact lens wear

How to Care for Your Lenses

  • Contact lenses must be properly cleaned and disinfected when you remove them to kill germs and prevent infections
  • All contact lens cases- should be cleaned daily and it is recommended that you replace your case every three months
  • Never reuse your contact lens solution
  • Dispose of contact lens solution in the lens case after each use and let the case air dry
  • Do not put your lens in your mouth and then in your eye
  • Never use homemade cleaning  solutions as they have been linked to serious eye infections
  • Any eye drops, even nonprescription ones, can interact with all types of contact lenses. Use the prescribed brand of solution or check with your optometrist before changing brands

Wear Your Lenses Properly

  • Wash your hands with soap prior to handling contact lenses or touching your eye
  • Do not share your lenses with someone else
  • Do not use fashion lenses (non-prescription color lenses) unless they are fitted by an optometrist
  • Do not purchase bootleg lenses
  • Wear lenses on the schedule prescribed by your optometrist
  • Dispose of your lenses at the interval prescribed by your optometrist

Remove Your Contact Lenses and Call Your Doctor When You Notice These Symptoms

  • Your eye is painful
  • You are sensitive to light
  • Your eye is red for more than two days
  • You have discharge from your eye
  • You have blurry vision
  • Your eye feels scratchy

Remember to book yearly contact lens and eye health exams for the protection of you eyes.

Clinic Information

For more information about contact lenses, see the Contact Lens Clinic and the complete Clinic Services listing of the U-M Kellogg Eye Center.

Last Modified: Wednesday, 19-Feb-2014 08:54:15 EST