Glare and Age: Acquisition of a Clinical Data Base for Aircrew Standards

Abstract : The trend towards a significant age-related decline in contrast sensitivity that we demonstrated in subjects aged 21 to 50 in previous studies prompted a replication with a large sample size and an investigation of scattered light, measured indirectly by disability glare, as a function of age. (1) We were unable to confirm the age-related decline of contrast sensitivity in the age range 21 to 50 with a large sample size, 30, in each decade. Contrast sensitivity to neither externally generated nor interference gratings changed significantly with age. (2) The high spatial frequency cutoff derived from the contrast sensitivity to 12, 16, and 20 cycle per degree gratings did not vary as a function of age. This is consistent with the fact that we selected only those subjects with 20/20 or better visual acuity. (3) Consistent with the lack of declining contrast sensitivity over this age range was the lack of a significant age-related increase in susceptibility to disability glare as measured by sensitivity to 4 and 12 cycles per degree gratings without and with glare. The interaction between age and glare condition was not statistically significant. (4) Increment threshold for a low mesopic background did not change significantly as a function of age. (5) There was a significant increase in the increment threshold limited to the glare condition for the oldest decade in the paradigm simulating night-time glare. (SDW)