Binocular Polaroid test.

A test is presented for the detection of small suppression scotomas in strabismic and in anisometropic patients. Three small light-spots (the central is polarized) are viewed through Polaroid filters placed in front of the eyes. This arrangement produces the perception of the central spot only from one eye, but normal fusion provides the perception of three light-spots. Complete suppression of the central light indicates the presence of a scotoma in the binocular visual field. An inhibition scotoma in the non-dominant eye was found in all cases of small angle esotropia and of anisometropic amblyopia.