Many models of binoculars will allow you to view in comfort while wearing eyeglasses or sunglasses. These binoculars have been designed to provide you with longer eye relief. Eye relief refers to the distance images are projected from the ocular lens to their focal point and can vary from 5mm to 23mm. If you want to use your binoculars with eyeglasses or sunglasses, look for binoculars that offer at least 15mm of eye relief.
Note: Without proper eye relief, the eyeglass wearer will not see the full field of view.
Binocular Eyecups: When using your binoculars, be sure you understand the correct use of the eyecups. All binoculars will allow you to adjust the eyecups. There may be a rubber eyecup that can be folded down or a newer type that either twists or slides up and down on the eyepiece of the binocular.
If you're an eyeglass wearer using binoculars, you always want to be sure you have the binocular eyecup rolled back (placed in the down position) while using your binoculars. This will allow you to see the widest possible field of view through your binoculars. Conversely, if you don't wear glasses, you'll enjoy your binoculars more if you leave these eyecups fully extended (placed in the up position). This will allow the binocular eyecups to just comfortably touch your face and help block out lateral light.