title: Test-retest reliability of the Arden Grating Test: inter-tester variability.
abstract: The aim of this study was to investigate the test-retest reliability of the Arden Grating Test (AGT), and to assess the extent to which any variance in AGT score on retest can be attributed to intra-subject and inter-tester differences. Twelve patients with various pathologies and whose contrast sensitivity covered a wide range were each tested twice by six testers. It was shown that variance attributable to testing by different clinicians accounted for approximately 25% of the total variance, and that the 95% confidence limits about any observed score were +/- 15 AGT units, which is about one quarter of the total dynamic range of the test. The large range of scores encompassed by the 95% confidence limits represents considerable unreliability, the consequence of which is a high misclassification rate, i.e. many false positives and false negatives, especially in the context of primary vision screening for which it was designed.
authors.affiliation: Visual Science Unit, Radcliffe Infirmary, Oxford, UK.
authors.forename: B C
authors.initials: BC
authors.lastname: Reeves
authors.forename: A R
authors.initials: AR
authors.lastname: Hill
authors.forename: J E
authors.initials: JE
authors.lastname: Ross
mesh_terms: D000328:Adult; D000368:Aged; D015350:Contrast Sensitivity / Q000502:physiology*; D005128:Eye Diseases / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009907:Optometry; D013997:Time Factors; D014787:Vision Tests / Q000592:standards*; D014792:Visual Acuity