A refractive eye exam, also referred to as a vision test or simply a refraction, is the test used to determine your vision prescription. It’s commonly performed as part of a comprehensive eye exam.

If you wear glasses or contacts or if you’ve ever had your vision tested, you’ve had a refractive eye exam. It’s the one that involves looking at a bunch of letters through a device while the eye doctor flips lenses back and forth, asking you which options look better.

“One … or two?”

“Two … or three?”

Sound familiar?

During this process, a refraction test will determine which type of refractive error is present, if any. The four standard refractive errors are nearsightedness, farsightedness, age-related farsightedness and astigmatism.