title: Explanation for good visual acuity in uncorrected residual hyperopia and presbyopia after radial keratotomy.
abstract: It has been observed that, after radial keratotomy (RK), uncorrected residual hyperopes may have better visual acuity than expected and that some presbyopes, corrected only for distance, have adequate near-vision. We offer a possible explanation for these observations by showing that the increased spherical aberration after RK may produce a second focus 1.5 diopters or more in front of the principal focus of the eye.
authors.affiliation: Southern California College of Optometry, Fullerton 92631.
authors.forename: R P
authors.initials: RP
authors.lastname: Hemenger
authors.forename: A
authors.initials: A
authors.lastname: Tomlinson
authors.forename: P J
authors.initials: PJ
authors.lastname: McDonnell
mesh_terms: D015350:Contrast Sensitivity; D006801:Humans; D006956:Hyperopia / Q000601:surgery*; D007646:Keratotomy, Radial; D011305:Presbyopia / Q000601:surgery*; D014792:Visual Acuity