A servomechanism is described which simulates the eye response in directing visual receptors. Feedback to provide corrective directing is based upon matching the images conducted to the “brain” by the neurons. The model uses photoelectric cells to receive the images. The image from each receptor unit (eye) is separated into two parts. The images are reproduced in the “brain” by illuminating light bulbs corresponding to the photoelectric cell receptors. A photoelectric scanner in the “brain” determines the amount of agreement of the images depicted by the several banks of light bulbs. Feedback leading to corrective directing (fusion) is produced by voltages generated in the scanner bridge circuit and causes a motor to oscillate the “eyeball” until images from both eyes are matched. Brain damage would cause continual oscillation of the eyeball and lead to the peculiar patterns drawn by some head-injured people.
J. R. SINGER, "Electro-Mechanical Model of the Human Visual System," J. Opt. Soc. Am. 47, 205-207 (1957)