A previously developed micro-computer system has been expanded to allow rapid display of text on three CRTs. A flexible software system allows workers with minimal computer expertise to create experimental text displays for studies of eye movements and head movements in simple reading tasks. Words or groups of words can be flashed in the center of any of the CRT screens at pre-determined rates and for pre-determined durations. All aspects of the display timing and control are determined by a disk file containing commands and text. This file is easy to create with standard word processing software. A simple hardware interface allows the computer's parallel pi-inter port to control text display on any combination of the three screens. Expansion to more screens is possible. The use of progressive lenses such as VARILUX II (R) is thought to require adaptation of the patient's head movements for effective reading ability. The system has been used in preliminary experiments to test these effects.
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