Correlation between Worth Four Dot Test Results and Fusional Control in Intermittent Exotropia

PURPOSE To compare the results of Worth 4-dot test (WFDT) performed in dark and light, and at different distances, with fusional control in patients with intermittent exotropia (IXT). METHODS Dark and light WFDT was performed for new IXT subjects at different distances and the results were compared with level of office-based fusional control. RESULTS Fifty IXT patients including 17 male and 33 female subjects participated in the study. A significant difference (P<0.05) was observed between levels of home and office-based fusional control (P<0.05). A weak correlation was present between the results of WFDT and level of office-based fusional control; the highest agreement (Kappa=0.088) was observed with dark WFDT performed at a distance of 4m. CONCLUSION Evaluation of fusional state by far WFDT, especially in a dark room, shows modest correlation with office-based fusional control in IXT patients and can be used as an adjunct to more complex tests such as far stereoacuity.