Abstract: A method and device which utilizes the Pulfrich stereo-illusion effect to screen for anterior visual system disease. The Pulfrich stereo-illusion effect occurs when viewing a pendulum moving perpendicular to the line of sight. If one eye is affected by anterior visual system disease, the pendulum appears to move in an ellipse--clockwise if the left eye is affected, counter-clockwise if the right eye if affected. A computer has software to generate an image of a "pendulum" bob. The patient views this image through a set of "virtual reality" goggles connected to the computer. The computer generates left and right images for presentation to each eye that mimic the varying perspective of real three dimensional objects viewed directly by the human eyes. The computer also generates a set of "neutral density" filters for each eye so that the degree of impairment in an eye may be quantified.