Worth four dot test

The Worth four dot test assesses fusion and suppression. The patient wears red-green glasses, red over the right eye and green over the left, and views four lights: one red at the top, two green at the sides and one white at the bottom. The patient reports how many lights they see:

Four lights: flat fusion. The bottom light looks white, pink or green depending on eye dominance.
Two red lights: the left eye is suppressed.
Three green lights: the right eye is suppressed.
Five lights: diplopia. Red to the right of green is uncrossed diplopia, an eso deviation. Red to the left is crossed diplopia, an exo deviation. Red above green is a left hyper deviation; red below green is a right hyper deviation.