Eyeglass Friendliness
Keep your eyeglasses on
If you wear eyeglasses, leave them in place when using binoculars; it's hard to find and focus quickly on a bird if you always have to remove your eyeglasses first. Plus, if you have astigmatism, you will lose the correction your glasses provide if you remove them, sacrificing image sharpness.
Eye Relief
Older binoculars required the eyes to be close to the eyepiece to see
the full field of view. Wearing glasses prevented this, giving a view
like looking down a tunnel and resulting in eye strain.
Many modern binoculars are more eyeglass-friendly. They overcome this
problem by featuring long eye relief. The optics direct the focal point
further back behind the eyepiece so the eye-glass wearer can see the
complete field of view.
Long eye relief binoculars are usually identified as such by the
manufacturer. Look for the amount of eye relief, given in millimeters,
in the model's technical specifications. Most eyeglass wearers need 12
to 15mm of eye relief to be comfortable.
Eyecups
Non-eyeglass wearers should use the binoculars with their eyecups in the raised position. Some designs have folding rubber eyecups; other designs snap up and down. The recently-developed turn-and-lock style of eyecup works well. Try binoculars with various eyecup styles and see which works best for you.
