Spectrum Scientifics Blog

When customers come into out store to look at binoculars they like to give them a test by looking through them. As might be expected many of our customers wear eyeglasses and ask ’should I take them off’ just before they put them up to their eyes.

The answer is a resounding ‘It depends’.

It depends on what kind of correction your eyes require, and it depends on the type of binoculars you are testing out (or, in the case of telescopes, the types of eyepieces).

If you have normal nearsightedness then the focusing mechanisms on binoculars will actually actually correct for your eyes. You do not need to wear your glasses. However, if the design of the binoculars provides enough eye relief you can use your binoculars without having to remove your glasses every time you want to look through them.

If you have a heavy astigmatism needing correction with your eyeglass prescription then you will invariably need binoculars (or eyepieces) with lots of eye relief.

So what is eye relief? Eye relief is the point past the glass of the binocular’s eyepieces where the image forms. Depending on the design this can be as little as as 7mm to as much as 25-30mm. Eye relief is important for eyeglass wearers because they cannot bring their eyes right up close to the eyepieces like non-eyeglass wearers. Usually, eyeglass wearers require a minimum of 16-17mm of eye relief to use the binoculars comfortably. And most eyeglass wearers will probably want more Eye relief than that.

Most higher end binoculars will have decent eye relief; enough for use by eyeglass wearers. However, most eyeglass wearers should seek out designs made for them such as the Orion UltraView binoculars which have 22mm of eye relief along with twist up eyecups (which means no time is wasted folding down flexible eyecups).

On the telescope side, many telescope users get frustrated with standard high-power eyepieces, which often have pinhole-sized viewing areas and minimal eye relief. In recent years many new eyepiece designs have come to market with eyeglass wearers in mind. The Orion Epic Eyepiece line is a good example. Even the high-power eyepieces of this series have not only good eye-relief (20mm) but also have wide lenses so that you don’t have to view through a pinhole!

If you wear eyeglasses and want to use telescopes & binoculars, you should seriously consider spending the extra money for products with long eye relief. Even if you do not have astigmatism, the comfort of not having to remove your glasses to view cannot be overstated.

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Filed under: Astronomy, Binoculars