General Requirements for Contacts

Contact lenses are convenient and cosmetically appealing, but they aren't for everyone. Certain circumstances and eye conditions prevent some people from wearing lenses. Knowing the basic requirements for contact lenses helps you decide what type of lenses you can wear if you are a good candidate for contacts.

Contact Lens Examinations

• An examination by an eye care professional who is licensed to fit contact lenses is the first requirement to be able to wear contact lenses. During your exam, your eye doctor uses a machine called a keratometer to measure the curvature of your cornea, the front surface of your eye. The measurement is called a "K-reading." The type of contact lenses you can wear depend on the amount of curve of your eye,
  If the surface of your cornea is irregular, you may require a rigid lens or a toric soft lens to correct astigmatism. In rare cases, certain curvatures cannot be corrected or require special lenses.

  Several appointments are usually required to make sure your lenses are fitting properly. A new exam and fitting is required every one to two years, as determined by your doctor.

Tear Production

• Contact lenses require moisture.

  Your eyes produce tears, even when you aren't crying. Tear film, a layer of moisture on the front of the surface of the eye, is important for the health of your eye and keeping it clean. A healthy amount of tear film is a basic requirement for contact lenses. Most people produce enough tears but in some cases, a patient's eyes may be too dry for contact lenses. Your doctor uses several tests to evaluate the dryness of your eyes during a contact lens examination.

Compliance

• Contact lenses must be cleaned and disinfected properly.

  One of the most important requirements for contact lenses is properly taking care of the lenses and your eyes. Eye infections are common when lenses are not cleaned and disinfected the right way or by using the wrong type of solutions, according the Ohio State University Optometry Services.

  Understanding and following your wearing schedule, the amount of time you are allowed to wear your lenses each day, is critical for the safety of your eyes. If you wear disposable lenses, you must replace them as directed by your eye doctor. If you are prescribed extended wear lenses, the kind that are meant to be slept in, only wear them for the amount of time indicated by your doctor. Never sleep in contact lenses that are not prescribed for extended wear.