nd hyperopia. His geometric approach can be thought of as a shapesubtraction model, where tissue of an appropriate profile is simply subtracted using an excimer laser to produce the desired surface curvature. Essentially, the cornea is treated like a piece of plastic to be sculpted into the ideal surface shape. The Munnerlyn approach, combined with empirical experience, has been relatively successful in correcting spherical and cylindrical errors for the majority of patients treated to date. However, only 50% to 85% achieve 20/20, despite greater than 90% of patients being satisfied. In addition, significant postoperative optical aberrations are produced using conventional algorithms 2-4 , encouraging the development of aberration-reducing ablation profiles. To improve the percentage of patients who achieve postoperative visual acuity of 20/20 or better, as well as to minimize optical aberrations, it is important to examine critically our current conceptual mod
Cynthia Roberts (Sat,) studied this question.