The objective of vision correction procedures is to decrease dependence on glasses and/or contact lenses by improving unaided visual acuity. Vision correction procedures are not precise, and may not result in perfect 20/20 vision; however, the majority of patients are able to function without glasses or contact lenses most of the time. Some people still require glasses to obtain their best vision for driving and/or reading. A few must still wear glasses or contact lenses all the time. *Patients who expect, or require, perfect 20/20 vision should not undergo refractive surgery. *
Much of the visual recovery occurs within the first several days after the procedure and is usually complete by 1-3 months after the procedure. In various studies, more than 95% of patients achieve at least 20/40 or better vision after LASIK. This represents legal driving vision and it is good enough for most sports and activities.
Correction may last indefinitely when vision is stable at the time of the refractive surgery. However, in cases of unstable vision, four to 10 percent of patients may require enhancement (retreatment for under-correction.) Those with severe vision problems may still need to use glasses or contact lenses for some time for reading and/or driving. The less refractive error a patient has, the greater the chance of achieving 20/20 vision after surgery.