Worth vs Polarized four-dot test.

A direct comparison between the Worth four-dot (W4D) and Polarized four-dot (P4D) flashlights is reported in a randomized trial on 107 unselected patients greater than 2.5 years old. The primary outcome variable was the interpretable response rate. Secondary outcomes were response time and age of test failure. There were 29 patients who failed to complete the W4D test, but only 10 patients who could not complete the P4D test, giving interpretable response rates of 73% and 91%, respectively (p < .001). The P4D test was found to be less dissociative and easier to administer. It also had a higher detection rate for fusion. We recommend its use as a tool in the clinical evaluation of binocular sensorial states.