Space shuttle suit alert system visual acuity problem.

The National Aeronautics and Space Administration (NASA) requested solution of a visual acuity problem that presbyopic astronauts had when viewing an alert system visual display attached to their Space Shuttle suits. Solutions wee analyzed in the context of constraints which prohibited major modifications of the suits. The solution to the problem was to mount Fresnel lens strips on the helmet so that presbyopic astronauts could view the visual display clearly.