title: Test-retest reliability of the College of Optometrists in Vision Development Quality of Life Outcomes Assessment.
abstract: BACKGROUND
  Medical diagnoses such as headaches, diplopia, nausea, and asthenopia are conditions that are often treated with optometric vision therapy. Improvement of such subjective conditions after a regimen of therapy is often difficult to objectively quantify. The goal of this study was to verify the test-re-test reliability of a new clinical survey instrument, the College of Optometrists in Vision Development (COVD) Quality of Life Outcomes Assessment, which allows the analysis of symptoms data.
  
  
  METHODS
  The first-year class of optometry students at the Oklahoma College of Optometry at Northeastern State University were administered the instrument in a group setting on two different occasions, two weeks apart. Nineteen students completed both test and re-test. Statistical analysis by the Wilcoxon Signed Rank Test and paired t test were performed.
  
  
  RESULTS
  Each subject reported some of the 30 symptoms on both test and re-test. The instrument was found to be reliable. Wilcoxon Signed Rank Analysis showed no significant differences in test-retest scores, either pooled or item-by-item. A paired t-test group and item analysis were insignificantly different between scores. Spearman's rho correlation for test-retest of each subject was 0.878. Eighty-nine percent (17 of 19) scored insignificantly different between administrations. Ninety percent of the items (27 of 30) were found to vary insignificantly between the two administrations.
  
  
  CONCLUSIONS
  The COVD Quality of Life Outcomes Assessment is a reliable tool to measure changes in symptoms on the basis of optometric intervention--specifically, vision therapy.
authors.affiliation: Northeastern State University College of Optometry, Tahlequah, Oklahoma, USA.
authors.forename: W C
authors.initials: WC
authors.lastname: Maples
mesh_terms: D006801:Humans; D009825:Oklahoma; D009907:Optometry / Q000379:methods*; D017063:Outcome Assessment, Health Care / Q000379:methods*; D011788:Quality of Life; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013334:Students; D011795:Surveys and Questionnaires; D014786:Vision Disorders / Q000175:diagnosis*; D014787:Vision Tests / Q000592:standards*