When most eye care professionals are evaluating the patient's visual acuity after laser vision correction, they typically focus on how well the person can read the eye chart and how closely they are to 20/20 vision with or without glasses. The concept that 20/20 vision represents perfect vision is misleading. Today we are setting a higher standard referred to as Quality of Vision. This term is used to describe the overall optical system of the person. There are many factors that may enhance or degrade your vision even though you may have 20/20 after laser vision correction.

When reading the eye chart you may be able to read the 20/20 line, this only measures how well you can read on black and white letters. One very important factor is contrast sensitivity. This is the ability to distinguish the minor shades between colours and how well they are defined. Contrast sensitivity also impacts the way you drive at night or how you may play sports during daylight. If you were playing tennis you may find it difficult to see the tennis ball because of the bright lights or road signs may appear difficult to read during the nighttime.