How To Use Binoculars With Glasses: Eye-relief & Eye-cups Explained

Using Binoculars with Eyeglasses

A question I often get asked is: How to use binoculars with glasses?, or If I wear eyeglasses, do I need to buy special binoculars?

The good news is that not only can you wear glasses when you use binoculars but you can get a view every bit as good as those who don’t. However, you do need to know a few things and be a little careful about what to look in the best binoculars for eye-glass wearers. I will try and explain as best I can:

It often depends on why you wear glasses:

If you wear glasses to correct far or nearsightedness, you may not actually need to use your eyeglasses when looking through your binoculars at all. This is because the focusing mechanism will allow for adjustment, thus correcting your vision.

If however, you use glasses for other reasons, like Astigmatism you will need to wear your prescription glasses when you are binning, or you will sacrifice valuable image sharpness.

The other issue many people have is even if you don’t need to wear your glasses whilst actually looking through binoculars, it is what to do with them whilst you are!

The obvious answer to that is to just remove your glasses, put them down or wear them around the neck with a safety cord. This sounds simple enough, but doing it all the time, over and over again can get really annoying and then there is always the risk of forgetting or losing them somewhere. The other issue with this is the time it takes. Whilst this may be fairly small, there is always that once in a lifetime sighting that you miss whilst you were swapping over.

Extended Eye-Cups on these Snypex Binoculars

Eye-Relief & Eye-cups

The solution: Binoculars with Long Eye Relief.

eye reliefWhat is eye relief?
Eye relief is the optimum distance between the ocular lens on the instrument and your eyes when using your binoculars. Any good quality binocular will come with adjustable eye-cups that enable you to get this distance just right so that you can see the full image without any bark rings forming on the edges.

For those that don’t need or wear glasses, the usual setting is to just have these eye-cups fully extended as the manufacturer usually designs the binocular so that the optimal eye-relief is at the same distance as the amount the eye-cups can extend. However, as we know different people have different shaped faces and so being able to micro-adjust them to get the distance exactly right for you can be important.

If you do wear eyeglasses, you should pay extra attention to the quoted maximum amount of eye-relief. This is because your glasses sitting in-between your face and the binocular increases the distance between the ocular lenses and your eye.

Thus most eye-glass wearers will need to twist or fold (depending on the type) the eye-cups down because your glasses take up the eye-relief space instead of the eye-cups.

So it is important that you get a pair of binoculars with enough eye-relief to allow for this:

How Much Eye-relief is Enough?

Most binoculars have an eye relief of greater than 10mm, but for most eye-glass wearers this is not enough to ensure that you get the full image and can comfortably see the full uninterrupted field of view without any dark rings on the edges.

In my experience, to be considered to have long eye relief and enough for those who wear glasses, you should be looking for a binocular that has at-least 16mm and ideally a little more.

Sure, an eye relief of 14 to 15mm is enough for some, but ideally and to be more certain I would suggest that you should look for binoculars that have more eye relief than this. These days there are many instruments that have 17, 18 and even 21mm, which you can take a look at by following the links under more information at the foot of this page.

Eye-Cups

The design of the actual eye-cup can be especially important if you wear glasses.

Most cheap binoculars older and many fixed focus designs will have simple rubber cups that you fold down. These are fine if you don’t require any adjustment and the folded down position is sufficient.

However, if you need or want some flexibility to alter the distance, then look for binoculars that have a twist up/down eye-cups. The best ones have a number of fixed “click” stops between fully extended and retracted. Others will have just enough friction and thus resistance to movement in order for you to position them at any point. For more on this, read this section on my reviews as this is one area that I check on every binocular that I test.

I hope that this helps in some small way in helping you to know when and how to use your binoculars with glasses.

For More Information:

Share

Comments are closed.