Medicine: Eye Control

DENIED the use of both arms and legs, the quadriplegic is usually condemned to inertia. But his sentence to stasis may soon be lifted by a switch that enables him to control a motorized wheelchair by eye movements alone. Manufactured by Hayes International Corp., and originally intended for use by astronauts, the Sight Switch uses eyeglass-mounted sensors to measure the intensity of light reflected from the whites of the operator’s eyes. The sensors then transmit their readings to a computerized box on the wheelchair.

Adjusted to the eye color of the wearer and programmed to ignore such involuntary actions as blinking, the switch allows the user to start, stop and reverse his wheelchair by practiced movements of his left eye, and to turn it by moving his right. Currently being tested at a veterans’ hospital in New York City and rehabilitation centers in Los Angeles and Houston, the Sight Switch —which costs $700 to $900—is remarkably easy to operate, even for the untrained. As one built-in safety feature, the computer is programmed to switch off the motor and bring the chair to a halt whenever one eye command for movement is not promptly followed by another.