PURPOSE: To determine the accuracy of different scales of the binocular fixation preference test and 10(Delta) fixation test in diagnosing amblyopia in patients with strabismus. METHODS: A prospective and masked diagnostic study was undertaken. We compared 3 binocular fixation preference test scales with interocular Early Treatment Diabetic Retinopathy Study (ETDRS) acuity differences. The 10(Delta) fixation test was used for patients with strabismus <10(Delta). Sensitivity, specificity, and likelihood ratios for amblyopia with an interocular difference of >or=2 lines were determined. Intra- and interexaminer agreements were measured. RESULTS: The study included 221 literate strabismic patients. The accuracy of the binocular fixation preference test was similar for all scales, with no advantage in combining them (Cronbach's alpha = 0.99). The sensitivity and specificity of binocular fixation preference among patients with strabismus >or=10(Delta) were 72.8% (95% CI, 59.7%-83.6%) and 77.6% (95% CI, 66.6%-86.3%), respectively; among patients with deviations <10(Delta), these were 89.6% (95% CI, 72.6%-97.8%) and 64.2% (95% CI, 44.0%-81.3%), respectively. The 10(Delta) fixation test did not alter this accuracy. Likelihood ratios were stronger for extreme grades of the binocular fixation preference test; however, in intermediate grades, they only changed by approximately 15% of the pretest probability of amblyopia. Intra- and interexaminer agreements were 76% (95% CI, 51%-100%) and 73% (95% CI, 48%-97%), respectively. CONCLUSIONS: The binocular fixation preference test is more useful for diagnosing amblyopia when the results indicate either a very strong preference or no fixation preference. The intermediate grades of the test were less accurate in our study, accounting for most of the false positives and negatives results.
PURPOSE: To determine the accuracy of different scales of the binocular fixation preference test and 10(Delta) fixation test in diagnosing amblyopia in patients with strabismus. METHODS: A prospective and masked diagnostic study was undertaken. We compared 3 binocular fixation preference test scales with interocular Early Treatment Diabetic Retinopathy Study (ETDRS) acuity differences. The 10(Delta) fixation test was used for patients with strabismus <10(Delta). Sensitivity, specificity, and likelihood ratios for amblyopia with an interocular difference of >or=2 lines were determined. Intra- and interexaminer agreements were measured. RESULTS: The study included 221 literate strabismic patients. The accuracy of the binocular fixation preference test was similar for all scales, with no advantage in combining them (Cronbach's alpha = 0.99). The sensitivity and specificity of binocular fixation preference among patients with strabismus >or=10(Delta) were 72.8% (95% CI, 59.7%-83.6%) and 77.6% (95% CI, 66.6%-86.3%), respectively; among patients with deviations <10(Delta), these were 89.6% (95% CI, 72.6%-97.8%) and 64.2% (95% CI, 44.0%-81.3%), respectively. The 10(Delta) fixation test did not alter this accuracy. Likelihood ratios were stronger for extreme grades of the binocular fixation preference test; however, in intermediate grades, they only changed by approximately 15% of the pretest probability of amblyopia. Intra- and interexaminer agreements were 76% (95% CI, 51%-100%) and 73% (95% CI, 48%-97%), respectively. CONCLUSIONS: The binocular fixation preference test is more useful for diagnosing amblyopia when the results indicate either a very strong preference or no fixation preference. The intermediate grades of the test were less accurate in our study, accounting for most of the false positives and negatives results.
Authors: Reed M Jost; Susan E Yanni; Cynthia L Beauchamp; David R Stager; David Stager; Lori Dao; Eileen E Birch Journal: JAMA Ophthalmol Date: 2014-07 Impact factor: 7.389