Subject: Binoculars, contacts, and glasses
Date: May 17 00:58:38 1996
From: WMulligan at aol.com - WMulligan at aol.com


As a birding ophthalmologist, I have followed with interest the comments on
the above. Its interesting that there almost as many opinions on this topic
as there are birders, but here are my observations:

If you can adapt to contact lenses, and most can, they are definitely
superior to glasses when using any binoculars, regardless of the eye relief.
They eliminate the rain problem, but more important, they solve the glare
problem. Those who use glasses with their binoculars have noted the severe
problem, on sunny days, with light entering the eye in the space between
their spectacles and their eyes. I find it almost impossible to avoid this
glare, which severely degrades observations.

Furthermore, light transmission through contacts exceeds that through any
glass or plastic spectacle lens, no matter how good the quality. For those
with astigmatism, both gas permeable and toric soft contacts will correct it.
For intermittent users, soft contacts are generally preferable, as they
require little or no adaptation.

For those unwilling or unable to wear contacts, you should ask your optician
to make your glasses with a very flat(0 to 1)front curve, or base curve.
This enables your binoculars to fit closer to your eye, and will improve
your field of vision. Clear lenses are best(anti-reflective coatings may
help, but they are expensive and wear off), as any tint will degrade your
vision in low light situations.

I am not convinced that the expensive high quality lenses will provide much
benefit to most people, but having an accurate and up-to-date refraction
will.

A note to you presbyopes("old eyes", or all those past 40-45): Contacts are
a problem for you, as it will be difficult to focus up close with your
distance correction, and bifocal contacts do not work very well. There are
two practical solutions: the easiest is to get a pair of magnifying reading
glasses at the drug store; the second is to be fitted for contacts for
"monovision". This means fitting one eye for distant vision( usually your
dominant eye)and the other for close. This does diminish your depth
perception some what, but many people find it a good solution. With
binoculars you simply adjust the one eyepiece to compensate for the
difference between your two eyes, so you have perfect binocular vision when
looking at the birds.

Bill Mulligan