While Mr. Collins is correct that there's little to be found on
effects of aging beyond 63 in the aeromedical literature, there's
quite a bit available elsewhere. The normal (expected) values for
many medical tests take age into account; most measures of human
performance do the same.

An interesting discussion of some the issues, along with some
references, can be found at:

http://cyberg.wits.ac.za/cyberg/sess.../age3/age3.pdf

There's no question that there's considerable individual variation in
the effects of aging. Research using tests which measure choice
reaction-time and vigilance (concentration and response over time)
suggests that both decline with age while simple reaction time and
reflex are much more resistent. If correct, this suggests that the
reflex hammer isn't sensitive enough.

For visual performance, contrast sensitivity and intactness of visual
fields appear to be important factors. These can be evaluated by
standard tests. If your eye doctor has the capability, ask to have a
Visual Fields test(Perimetry) performed as part of your eye exam.

Raphael Warshaw
Claremont, CA