Titre du document / Document title

Repeatability of refraction and corrected visual acuity in keratoconus

Auteur(s) / Author(s)

The Clek Study Group
DAVIS L. J. ⁽¹⁾ ; SCHECHTMAN K. B. ⁽²⁾ ; BEGLEY C. G. ⁽³⁾ ; SHIN J. A. ⁽⁴⁾ ; ZADNIK K. ⁽⁵⁾ ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

⁽¹⁾ University of Missouri-St. Louis School of Optometry, St. Louis, Missouri, ETATS-UNIS
⁽²⁾ Washington University School of Medicine, Division of Biostatistics, St. Louis, Missouri, ETATS-UNIS
⁽³⁾ Indiana University School of Optometry, Bloomington, Indiana, ETATS-UNIS
⁽⁴⁾ Southern California College of Optometry, Fullerton, California, ETATS-UNIS
⁽⁵⁾ The Ohio State University College of Optometry, Columbus, Ohio, ETATS-UNIS

Résumé / Abstract

Purpose. The purpose of the test-retest phase of the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study was to determine the repeatability of the various parts of the CLEK Study protocol. This paper presents the test-retest parameters of the refraction protocol. Methods. We examined 138 CLEK Study-eligible patients on two occasions (median, 90 days; range, 22 to 268 days). All patients underwent subjective refraction on two occasions, and contact lens over-refractions were performed either over the patient's habitual rigid contact lenses or over a trial rigid contact lens equal in base curve to the steep keratometric reading in nonrigid contact lens wearers. Results. Mean interoccasion differences ± SD were -0.32 ± 2.91 D and -0.17 ± 1.39 D for subjective refraction sphere and cylinder power, respectively, and the mean absolute difference for subjective refraction cylinder axis was 18.1 ± 20.2°. The mean interoccasion difference ± SD for high-contrast visual acuity with subjective refraction was 0.38 ± 10.9 letters correct. Mean interoccasion differences ± SD were -0.11 ± 0.81 D and 0.02 ± 0.67 D for contact lens over-refraction sphere and cylinder power, respectively, and the mean absolute difference for contact lens over-refraction cylinder axis was 11.6 ± 9.9°. The mean interoccasion difference ± SD for visual acuity with contact lens over-refraction was 0.50 ± 5.2 letters correct and 0.71 ± 6.9 letters correct for high- and low-contrast visual acuity, respectively. Conclusions. The repeatability of subjective refraction in keratoconus patients is good but somewhat lower than that found in nondiseased eyes. Only 36% of our repeat measures of sphere power from subjective refraction fell within 0.50 D of each other, compared with more than 90% in studies of normal eyes.

Revue / Journal Title

Optometry and vision science   ISSN 1040-5488   CODEN OVSCET 

Source / Source

1998, vol. 75, n^o12, pp. 887-896 (35 ref.)

Langue / Language

Anglais

Editeur / Publisher

Lippincott Williams & Wilkins, Hagerstown, MD, ETATS-UNIS  (1989) (Revue)

Mots-clés anglais / English Keywords

Keratoconus ; Repeatability ; Refraction ; Visual acuity ; Exploration ; Human ; Eye disease ; Keratopathy ;

Mots-clés français / French Keywords

Kératocône ; Répétabilité ; Réfraction ; Acuité visuelle ; Exploration ; Homme ; Oeil pathologie ; Kératopathie ;

Mots-clés espagnols / Spanish Keywords

Queratocono ; Repetibilidad ; Refracción ; Acuidad visual ; Exploración ; Hombre ; Ojo patología ; Queratopatía ;

Localisation / Location

INIST-CNRS, Cote INIST : 6826, 35400007328579.0070