A refraction test also called a vision test, is usually performed as a part of a routine eye examination. The purpose of this test is to determine whether glasses or contact lenses are required for best-corrected vision.
A value of 20/20 is normal vision. This means that individuals who have 20/20 vision are able to read letters that are 1 centimeter tall from 6 meters away. Individuals who don’t have 20/20 vision have what is called a refractive error. A refractive error means that the light is not bending properly when it passes through the eye. The refraction test will tell the doctor what prescription lens should be used in order to achieve 20/20 vision.
Astigmatism (abnormally curved cornea causing blurred vision)
Presbyopia (inability to focus on near objects that develop with age)