Performing contact lens exams
The goal of a contact lens exam and fitting is to determine the best contact lens style and size to fit your eyes. The contact lens exam includes the following measurements:
Corneal curvature: the curve of the cornea is measured with a keratometer. This measurement dictates the best shape and diameter for your contact lenses. Corneal curvature measurements may be combined with aberrometer measurements to identify higher order visual aberrations.
- Eye surface irregularities: The exam may reveal that your eye’s surface is irregular due to astigmatism. Patients with astigmatism are given a special type of contact lens known as a toric lens, which is shaped to offset the abnormalities.
- Pupil and iris size: Pupil and iris measurements are taken with an instrument called a biomicroscope. These measurements are used to help choose the proper size and orientation of contact lenses.
- Tear film testing: Tear film testing is conducted to ensure that your eyes are capable of keeping contact lenses moist with tears. Tear production can be evaluated with a slit-lamp test or with a small paper strip placed under the lower eyelid.
If you are considering contact lenses, schedule an appointment with an experienced optometrist.