diode led representatively shown and identified by reference numeral 16 diffusely illuminates the region of the front of the eye about ten percent 10 of the light is transmitted through beam splitter bs 3 which light passes through lens l 5 lens l 5 forms an image of the pupil and the front of the eye in the plane of a video sensor c 1 the video output from video sensor c 1 is displayed on an operator 39 s monitor on computer screen shown in fig3 to provide a view of the eye and of the pupil if the patient 39 s eye is focused at infinity the light reflected from each point on fundus 14 will be collimated as it is incident on lens l 4 therefore 90 of the light reflected from beam splitter bs 3 will form an aerial image of the fundus in the focal plane of lens l 4 which focal plane is represented by a dashed line identified as fi fundus image the light passes through lens l 6 which lens is at its focal distance from fundus image fi thus lens l 6 will collimate light from each point on the fundus further because the light considered as originating in the plane of pupil p is collimated by lens l 4 lens l.