Quality of vision and freedom from optical correction after refractive surgery.

early half of the population of North Amercia has myopia; the prevalence of myopia in other populations ranges from 2 to 60%, as McCarty and colleagues document in this issue of the Journal (pp. 229-234). The ideal goal of refrac-tive surgery for such individuals is to eliminate the need for distance optical correction and to allow them to see as well as—or better than—they could with spectacles or contact lenses. In 1997, we have only partially achieved that goal. In this issue of the Journal (pp 300-301), Werblin 1 opines that the goal of refractive surgery is 20/20 or better uncorrected visual acuity and " patients will not be happy until refractive surgery is able to satisfy this need. " After contemporary refractive kera-totomy, photorefractive keratectomy (PRK), excimer laser in situ keratomileusis (LASIK), intrastromal corneal ring segment insertion, and phakic intraoc-ular lens (IOL) implantation, approximately 50 to 60% of patients with myopia of-10.00 diopters (D) or less, see 20/20 or better uncorrected at approximately 1 year after surgery, but well over 90% could see 20/20 or better before surgery—with optical correction. At the 20/40 level, commonly referred to as driver's license vision, we are doing much better— over 90% of operated eyes achieve this level. A significant proportion of patients wear an optical correction after refractive surgery—either part-time (eg, night driving) or full-time. For example, in the PERK study at 6 years after surgery, 36% (167) of patients younger than 40 years of age wore lenses for distance or near vision. 2 Unfortunately, published data on how many patients wear spectacles and contact lenses after refractive surgery is almost nonexis-tent—a remarkable indictment of clinical reporting from the refractive surgical community, since the most important criterion of success for patients who have refractive surgery is freedom from corrective lenses. It is not only the refractive outcome after surgery that determines spectacle wearing status, but also the stability of refraction over time. Changes in refraction may occur from the surgical procedure itself. A hyperopic shift after radial keratotomy has been well documented 3 ; shorter corneal incisions may decrease the hyperopic shift 4 but long-term follow-up data at 3 to 10 years have not been published. Sawelson and colleagues 5 attributed the hyperopic shift to physiological changes in the refractive state of the eye rather than to continued flattening of the cornea, a contention refuted by the data of Ellingsen and colleagues …