A picture or two might help.
Ed
Of course the FOV is fixed on each binocular, but the older models feature fairly deep eye cups which hinder eye glass wearers from getting the potential FOV. Unscrewing and removing the cups will allow greater eye relief, but then one has to contend with scratching the eye glasses when the binoculars are pressed against glasses themselves. The sound of metal hitting glass is not good, and many eye glasses have special coatings on the front surfaces which can be marred from rubbing against the metal rims surrounding the ocular lens when the binoculars are mounted.
I note that many birders who don't need corrective lens usually wear sun glasses outdoors. Using the older binoculars is less likely to occur then, even though many older binoculars have excellent optics.
There is a simple, inexpensive, and effective way to maximize your FOV with these older binoculars. After removing the eyecups, place a ring of non skid tape with the adhesive backing so it surrounds the ocular lens and press it in place.
3-M makes a suitable non-skid sticky back tape for making the rings. It has the rubbery surface, not the grit surface. One can punch out the rings with leather punches, or trace the circles on the paper side of the tape which is removed after the rings are cut out - sharp sissors work well. The rings will stay put, yet are easily removed. I take the eye cups and run a string through them with a tag attached identifying which binocular they came from and then store them away.
While this system won't permit full view with some models, it nonetheless will increase the FOV and protect your eye glasses at the same time.
John
Good idea, John.
A picture or two might help.
Ed
Ed - I'm not advanced enough in my computer skills to down load images, but think of a very thin flat washer (circular) cut dimensionally to expose the ocular lens in the center opening with a width of say 4 mm from inside to outside edge. 3M makes an ideal strip with sticky back coming off rolls in different widths. Three inches in length by one inches in width is enough to fashion two rings. I've used velcro as a substitute with the soft hook facing up, but it tends to collect tiny pieces of everything, while the rubbery surface of the 3M tape is easy to keep clean. A real low cost fix that stays in place until you want to remove the rings. Also if the outer edge of the tape ring is carefully cut away, the eye cups can be screwed over them without a problem., keeping everything together. John