Quote Originally Posted by c6h6o3
Go to an opthalmologist so that you can rule out macular degeneration, glaucoma or cataracts.

I've worn glasses since I was 14 and have never had any problems with viewfinders. One of my lenses is -10 diopters. If you have trouble seeing close (i.e. need reading glasses) you might want to take your glasses off to look closely at the viewfinder. You will definitely need your glasses on to use the magnifier.

I always take them off when I am under a darkcloth.
Excellent advice from c6h6o3!

I have been wearing glasses since I was 4 years old (stigmatism - both eyes and convergence problems). I use WLF with MF TLRs and SLRs plus focus magnifiers with no problems. You may need to remove your glasses in order to see the full image (for framing/composition).

I usually leave my glasses (bifocals) on when I am under my BlackJacket using a LF camera.