The use of yoked base-up and base-in prism for reducing eye strain at the computer

Eye strain continues to be one of the chief complaints of people working at video display terminals. The increase in extorsion observed on elevation of gaze at near point may induce binocular disruption and strain. Binocular base-up and base-in prism might mitigate some of the visual complaints of computer users because they decrease the elevation and convergence required. A double blind study of 30 computer users indicates a significantly greater preference for a lens combining prism and plus power than for plus lenses having no prism.