If certain activities are getting harder to accomplish due to poor vision, it’s beneficial to talk to an eye doctor to see if contact lenses or eyeglasses could fix the problem. To determine what prescription would best correct your vision, your eye doctor will perform refraction, also known as a vision test.
The Refraction Process
During your eye exam, an ophthalmologist or optometrist will guide you through the refraction testing portion. This is a painless procedure that requires no amount of prior preparation. However, those who wear contacts to their appointment will likely need to remove them before the test can begin.
You will start by sitting in a chair 20 feet away from an eye chart to look through the phoropter.
The Phoropter
This device helps the eye doctor evaluate the condition of a patient’s refractive error in each eye. The phoropter features several lenses and settings that the doctor can switch out quickly—your doctor will move between the various options, asking for your feedback about the clarity of each one. Together, you will narrow down the lenses and settings that combine to give you the greatest vision correction and the clearest eyesight.
Why Test for Refraction Errors?
Patients with undetected refraction errors may not realize their eyesight could be clearer. With a refraction test, a patient with undetermined vision issues can understand the source of their eyesight issues and start to use customized corrective lenses or even undergo LASIK to help restore clear vision.
Common Refraction Issues in Patients
Some of the most common refraction issues that patients experience are:
- Astigmatism, or an abnormal curve to the cornea
- Myopia, or nearsightedness
- Hyperopia, or farsightedness
- Presbyopia, or an age-related condition causing patients to not focus on close objects
How Often Should a Patient Have a Refraction Test?
Patients without refractive errors should undergo testing every 3 to 5 years unless they begin noticing changes to their vision. If you feel your vision is becoming less clear, schedule a refraction test and a complete eye exam right away.
Patients with refractive errors should have an eye exam every 1-2 years. Schedule one sooner if you notice your eyesight worsening while wearing glasses or contacts.