I switched to soft contact lenses expressly for working in the field doing
bird observations. Glasses have never worked well for me in the field; I
have god-awful peripheral vision with them on, they get all bleary and
unusable with any mist, rain, or snow, they keep fogging up if I am
hopping in and out of a warm truck on a cold day, and they hurt my ears.
I suppose glasses might work okay in a warm dry habitat...but I always
seem to be birding in damp cold habitats.

So I switched to disposable soft contacts for my fieldwork on the Alaskan
tundra. They worked great. (I do not have serious astigmastism, so that
wasn't a problem.) The only problem I had was if I was staring fixedly at
one bird for a very long time (over 10 minutes) while the wind was blowing
sideways against my face, there would be a sort of wind tunnel effect
between the binocs & my eyeballs, which sometimes would dry the contacts
out, and, rarely, flip them out entirely. Self-disposing contacts!

The oddest situation was when I caught a female Lapland longspur at the
nest and was crouching down getting a blood sample from her wing vein.
Her mate walked right past me with a mouthful of bugs and blundered into
the net, dropped his bugs and started alarm-calling in a panic, the babies
in the nest started screaming, and suddenly one of my contacts blew out
right onto the female's wing. I sat there paralyzed for a moment, my
brain going "Finish blood sample! Save contact! Rescue male! Feed babies!"

That's the only time I put a contact back in with a longspur in my hand.

Kathleen