Reliability of Fixation Preference for Detecting Amblyopia in Strabismic Patients

Purpose: to evaluate the association between fixation preference (fp) and amblyopia instrabismic patients.methods: this study includes 50 patients with horizontal, vertical or mixed strabismusof at least 10 prism diopters. best-corrected monocular visual acuity (va) was measured using snellen e-chart and the presence of amblyopia was determined accordingly; fp was evaluated and graded from 0 to 3.results: of 50 patients, including 27 female and 23 male subjects, 29 (58%) patients hadfp but 18 (36%) subjects were truly amblyopic. overall, the sensitivity and specificity offp for detection of amblyopia was 88.9% and 59.4% respectively. the positive predictivevalue (ppv) and negative predictive value (npv) were 55.2% and 90.5% respectively.sensitivity, ppv and npv were significantly higher in esotropic as compared toexotropic patients. strong monocular fp was correlated with more than 3 lines ofinterocular difference (iod) in visual acuity (p=0.001).conclusion: although fp is not an ideal method for diagnosis of strabismic amblyopia,it has high sensitivity, ppv and npv in esotropic patients and in subjects with morethan 3 lines of iod in va.