Preliminary Evaluation of Visual and Flight Performance of Three Current Multifocal Contact Lens Designs for Presbyopic US Army Aviators

摘要

U.S. Army aviators have been authorized to wear contact lenses for aviation duties with special waiver since 1991. The authorized contact lens modality is the single-vision soft contact lens that corrects for 20/20 distance and near. As aviators become presbyopic, they often have to return to bifocal spectacle wear or readers over their distance contact lenses in order to complete their aviation duties. Spectacles introduce interface problems with head-mounted displays and night vision goggles. This pilot study evaluated the potential utility of multifocal contact lenses to provide adequate visual and flight performance for presbyopic aviators. Bifocal spectacles or readers provide better levels of visual performance than any of the three multifocal contact lenses evaluated. Flight performance in a UH-60 simulator under daytime conditions was not decremented with the multifocal contact lenses evaluated in this study; however, this study did not evaluate night flight, interface with head-mounted displays or night vision goggle flight performance. Studies specific to the Apache flight environment are being considered since visual performance remained within norms and Apache pilots are faced with greater interface problems with bifocal spectacles and head-mounted displays and protection mask configurations than pilots in other aviation platforms. Many Apache pilots have been permanently Wounded or converted to other platforms due to the onset of presbyopia and spectacle compatibility issues in the cockpit Multifocal contact lenses, when fit to specific parameters, may be an option under special circumstances where spectacles would lead to reduced performance.