Contact Lens

At Mission Optometry, we are happy to offer contact lens exams to our patients. We also offer education and training of contact lens use and care to first-time users of contact lens. For many people, contact lens offer greater freedom and convenience. Please review the information below to see if contact lens would be a good fit for you!

Comprehensive Exam First

Before a contacts lens exam, a comprehensive eye exam must be performed. In this exam, your eye doctor determines your prescription for corrective lenses (the glasses prescription) and checks for any eye health problems or other issues that may interfere with being able to wear contact lens.
If all looks good during your eye exam, the next step is a contact lens consultation and fitting. 

Contact Lens Measurements

Because every eye is slightly different, there are a variety of types and sizes of contact lens. If the curvature of a contact lens is too flat or too steep for your eye's shape, you may experience discomfort or even damage to your eye. Measurements that will be taken to determine the best contact lens size and design for your eyes include:

• Corneal curvature. An instrument called a keratometer is used to measure the curvature of your eye's clear front surface (cornea). This measurement helps your doctor select the best curve and diameter for your contact lenses.
  If your eye's surface is found to be somewhat irregular because of astigmatism, you may require a special lens design known as a "toric" contact lens. At one time, only gas permeable contact lenses could correct for astigmatism. But now, there are many brands of soft toric lenses, which are available in disposable, multifocal, extended wear and colored versions.

In some cases, a detailed mapping of the surface of your cornea (called corneal topography) may be done. Corneal topography provides extremely precise details about surface characteristics of your cornea and creates a surface "map" of your eye, with different contours represented by varying colors. 

• Pupil and iris size. The size of your pupil and iris (the colored part of your eye) can play an important role in determining the best contact lens design, especially if you are interested in GP contact lenses. These measurements may be taken with a lighted instrument called a biomicroscope (also called a slit lamp) or simply with a hand-held ruler or template card.
• Tear film evaluation. To be successful wearing contact lenses, you must have an adequate tear film to keep the lenses and your cornea sufficiently moist and hydrated. This test may be performed by placing a liquid dye on your eye so your tears can be seen with a slit lamp, or with a small paper strip placed under your lower lid to see how well your tears moisten the paper. If you have dry eyes, contact lenses may not be right for you. Also, the amount of tears you produce may determine which contact lens material will work best for you.

Contact Lens Prescription

Often, trial lens will be given in order to verify fit and the correct prescription. The doctor will have the patient put on the trial lens and then will evaluate the position and movement of the lens. If you are a first-time user of contact lens, you will be given instructions on how to care for your lenses and how long to wear them. You will also receive training on how to handle, apply and remove the lenses. 

Once you find a contact lens that fits properly, is comfortable for you, and provides good vision, your doctor will write a contact lens prescription for you. This prescription will designate the contact lens power, the curvature of the lens (called the base curve), the lens diameter, and the lens name and manufacturer. 

Regardless of how often or how long you wear your contact lenses, your eyes should be examined at least once a year to make sure your eyes remain healthy and tolerant of contact lens wear.

Article ©2015 Access Media Group LLC. All rights reserved. Reproduction other than for one-time personal use is strictly prohibited.