By integrating the eye and head-position monitoring devices, the present authors developed an eye-controlled human/computer interface based on the line-of-sight and an intentional blink to invoke commands. Also modified was an existing calibration method to reduce the visual angle between the target center and the intersection point of the derived line-of-sight. The reduced visual angle allowed 108 or more command blocks to be displayed on the 14 inch monitor with the target acquisition probability (hit rate) of 98% when viewed at a distance of 500 mm apart. This could represent all keys of the standard keyboard on the monitor. An active triggering method, using an intentional blink, was a feasible and efficient alternative to invoke commands with total triggering time of 0.8 s or less. The system could be used by normal people as well as handicapped individuals as a new human/computer interface. Copyright (C) 1996 Elsevier Science Ltd