“…Of Active Duty, Reserve and National Guard aviators wearing spectacles in 1989, 8 percent, 15 percent and 20 percent, respectively, were presbyopic. Shannon and Mason (1994) and Stone (1993) showed that there was a marked increase from 1986 to 1992 in percentage of Army aviators over 40. A 1989 U.S. Air Force study The refractive problems described above have traditionally been corrected using spectacle lenses.…”