If you want to look through binoculars with spectacles, it is important that they are also designed to accommodate this. But this is often not indicated by the manufacturer. Some binoculars are not suitable for observing with spectacles, these would only display a very small and cropped field of view.
It is important that the exit pupil lies further out at around 20mm distance from the eyepiece, in order to offer the spectacles wearer the best possible view. In addition, the eyecups should not get in the way. With quite a lot of binoculars you can retract them. They are made of hard plastic.
On the other hand, there are also soft eyecups, which can be folded down. These are really soft on the eye, but can become brittle over time when the plasticizers inside evaporate.