Refraction test: Also termed vision test, the refraction test is an examination that tests an individual's ability to see an object at a specific distance. The test is performed by an optometrist or ophthalmologist in the doctor's office. The refraction test involves looking through a device to read letters or recognize symbols on a wall chart through lenses of differing strength which are moved into and out of the device. This test is performed as part of a normal examination of the eye to determine whether an individual has normal vision. It is also used to determine the prescription for eyeglasses or contact lenses.