If you wear spectacles, one specification decides whether a pair of binoculars works for you, and it is not magnification or aperture. Eye relief is the distance behind the eyepiece at which the full field is visible, and glasses push your eye further back than that distance often allows.
What eye relief is
The eyepiece forms its exit pupil a fixed distance behind the glass. Put your eye there and you see the whole field; further back and the field shrinks, as though looking down a tube. Spectacle lenses hold the eye roughly 12 to 15 millimetres back, so a pair with 14mm or more of eye relief is usable with glasses and one with 10mm is not.
Setting the eyecups correctly
Binoculars have eyecups that twist or fold down. With glasses they should be fully retracted so the spectacle lens can sit close to the eyepiece; without glasses they extend to hold your eye at the right distance. Most complaints about a narrow field come from having this the wrong way round rather than from the binoculars.
Whether to wear them at all
If your prescription is mainly spherical, you can often take the glasses off and correct with the focus wheel and dioptre adjustment. If you have significant astigmatism, the binoculars cannot correct it and you should keep the glasses on, which makes eye relief the specification to shop by.
Questions people ask about binoculars
Can you use binoculars with glasses?
Yes, with a pair offering at least about 14mm of eye relief and with the eyecups fully retracted.
What is eye relief on binoculars?
The distance behind the eyepiece where your eye sees the full field. Spectacle wearers need more of it, because their eyes sit further back.
Should I take my glasses off to use binoculars?
If your prescription is simple, often yes, and the focus wheel will compensate. With astigmatism, keep them on and buy for eye relief.