TY - JOUR
T1 - Defining Real Change in Prism-Cover Test Measurements
AU - Holmes, Jonathan M.
AU - Leske, David A.
AU - Hohberger, George G.
N1 - Funding Information:
This study was supported by National Institutes of Health, Bethesda, Maryland, Grants EY015799 (Dr Holmes), Research to Prevent Blindness, Inc, New York, New York (Dr Holmes as Olga Keith Weiss Scholar and an unrestricted grant to the Department of Ophthalmology, Mayo Clinic), and Mayo Foundation, Rochester, Minnesota. The authors indicate no financial conflict of interest.
PY - 2008/2
Y1 - 2008/2
N2 - Purpose: To describe the interobserver test-retest variability of both simultaneous prism and cover testing (SPCT) and alternate prism and cover testing (APCT) in horizontal deviations, and to calculate 95% limits of agreement that might be used to define real change. Design: Prospective cohort study. Methods: Twenty-three patients with sixth nerve palsy and three controls were independently examined by two experienced strabismus surgeons. SPCT and APCT were performed at distance and near fixation. Test-retest variability and agreement between tests were evaluated using Bland-Altman plots and 95% limits of agreement were calculated. Results: For SPCT, the 95% limits of agreement half-widths were 6.3 prism diopters (pd) at distance fixation and 6.9 pd at near. For APCT, the 95% limits of agreement half-widths were 10.2 pd at distance and 9.2 pd at near. Conclusions: Based on 95% limits of agreement half-widths between two examiners, a change in strabismus measurements of less than 10 pd may be attributable to test-retest variability. Changes of 10 pd or more are likely to represent real change and might be used as the threshold for management decisions.
AB - Purpose: To describe the interobserver test-retest variability of both simultaneous prism and cover testing (SPCT) and alternate prism and cover testing (APCT) in horizontal deviations, and to calculate 95% limits of agreement that might be used to define real change. Design: Prospective cohort study. Methods: Twenty-three patients with sixth nerve palsy and three controls were independently examined by two experienced strabismus surgeons. SPCT and APCT were performed at distance and near fixation. Test-retest variability and agreement between tests were evaluated using Bland-Altman plots and 95% limits of agreement were calculated. Results: For SPCT, the 95% limits of agreement half-widths were 6.3 prism diopters (pd) at distance fixation and 6.9 pd at near. For APCT, the 95% limits of agreement half-widths were 10.2 pd at distance and 9.2 pd at near. Conclusions: Based on 95% limits of agreement half-widths between two examiners, a change in strabismus measurements of less than 10 pd may be attributable to test-retest variability. Changes of 10 pd or more are likely to represent real change and might be used as the threshold for management decisions.
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U2 - 10.1016/j.ajo.2007.09.012
DO - 10.1016/j.ajo.2007.09.012
M3 - Article
C2 - 18045567
AN - SCOPUS:38349181571
SN - 0002-9394
VL - 145
SP - 381
EP - 385
JO - American journal of ophthalmology
JF - American journal of ophthalmology
IS - 2
ER -