My eye doctor says I need a refraction. What does that mean?
A refraction is the examination an ophthalmologist (eye M.D.) or optometrist (O.D.) uses to measure the amount of vision correction you need. If you wear glasses or contacts or are interested in refractive surgery, this exam is essential. Your doctor needs to evaluate your vision carefully to write an accurate prescription for corrective lenses or plan refractive surgery.
If you don’t wear glasses or contacts, you might still need a refraction to determine how well you can see. Your doctor uses an instrument with built-in corrective lenses to test your vision. Reasons to do this include:
- Your eyes change as you get older. Even if you’ve never worn glasses or contacts, your doctor might discover you actually see better with corrective lenses now.
- Some medical conditions affect your eyes and vision. If you have one of these conditions, your doctor needs to do a refraction as part of a complete eye exam.
The results of the test are used to diagnose the following conditions:
- astigmatism, a refractive problem with the eye related to the shape of the lens, which causes blurry vision
- hyperopia, which is also known as farsightedness
- myopia, which is also known as nearsightedness
- presbyopia, a condition related to aging that causes lens of the eye to have trouble focusing
The results of the test can help diagnose the following conditions:
- macular degeneration, a condition related to aging that affects your sharp central vision
- retinal vessel occlusion, a condition that causes the small blood vessels near the retina to be blocked
- retinitis pigmentosa, a rare genetic condition that damages the retina
- retinal detachment, when the retina detaches from the rest of the eye
Regular eye examinations are crucial for maintaining the health of your vision. They’re a routine part of an eye doctor visit and require no preparation on your part. They can help your doctor diagnose and treat conditions such as glaucoma and determine the need for corrective lenses, among other things. Healthy adults should have a refraction test every two years, while children need them every one or two years beginning at age 3.