ABSTRACT
Sometimes while wearing dark sunglasses you may feel slightly out of touch with the world. In fact, investigations of the Pulfrich stereophenomenon suggest that this impression may be correct. Sunglasses decrease the intensity oflight reaching your eyes and slow your visual responses (i.e. increase your visual latency). The amount of this slowing is slight, although Walker (1978) calculates that it could contribute to an automobile accident. However these visual latency changes can produce remarkably strong effects when one eye is shaded and the other is not. Under these circumstances the visual latency of the two eyes is different.
