Now one of the things I found which made me unable to observe through a telescope for very long, is trying to keep one eye closed while looking through the other. Having owned a Denkmeier binoviewer in the past and only used it very occasionally for binoviewing and not quite enjoying it, I thought that perhaps I need to be thinking of using something to cover the left eye for me to reduce eye strain. That way I did not need to try and keep one eye closed at all times. Hence it dawned on me about getting an eye patch to do the job.
Inspired by Nick Fury of the Avengers, who wears an eye patch on his bad (left) eye, I decided to buy an eye patch from Amazon for £3.99. It has foam padding where it is supposed to fit against the eye socket, and the center does protrude out to prevent pressing against the eye. It definitely blocks all light getting to the eye.
Eyepatch with my glasses fitted on (I made cuts to the foam to allow for the glasses to fit better)
Now as I wear glasses even for astronomy observation due to astigmatism, I did try to adapt this to use with my glasses. Unfortunately it sticks out too much to fit inside my glasses, and feels too tight when fit outside my glasses. It will work very well for someone without glasses, but it just doesn’t work for me. So back to the drawing board.
Then recently I noted that there were eye patches which could fit onto glasses for children with lazy eyes on Amazon. These come in different designs to appeal to children (e.g. spiderman, batman). But for me, to keep with the one-eyed theme I decided to get one with a Minion on it. These patches cost more at £7.99 plus delivery. I did enquire with the company as to what the inner lining looked like and they responded relatively quickly to say that it was black. Perfect. Hence I had no hesitation to order one (left eye version) from them.
I have to say that the eye patch came very quickly two days after ordering it. First impressions are that it looks well constructed and should last. And it is washable should it become stained.
To fit the eye patch, you simply slip the stem of the glasses through the opening on the broader side and advance the patch until it covers the entire side of the glasses.
There is also a little slit on the broad side for the nose pad of the glasses to stick out. I did find that if the black lining is not pressed down onto the glasses, then you may feel the eye lashes brushing against it which can be a tad irritating. But when fit properly that is not a problem at all.
Now it does come both in a right eye and a left eye version, as the design will be the right way up for each version; you would have an upside down Minion if you bought for the wrong eye.This is not an issue for me, as I am only wearing it for looking at the sun in the daytime, when I would also have a black t-shirt covering my head to block any unwanted light (which already looks funny), or at night when it is dark and nobody is looking at me anyway.
Certainly this is probably the best way to aid visual observation in astronomy, without resorting to buying a binoviewer and multiple eyepieces to go with this. Do note that it only blocks light getting to the eye from the front and side, but will not completely block all light – hence in the daytime I would still use the black t-shirt to block as much light as possible to benefit the viewing eye as well.
And it will reduce the eye strain from trying to keep one eye shut as they can both remain open while I just look through the right eye. I would definitely recommend this, if the glasses will fit (my glasses which are 33-34mm tall just fits into this). But I would expect that it could probably fit up to 35mm tall frames but no more, without the risk of breaking the threads. The first eye patch will work well for non-spectacled people.
So there are eye patches available for both spectacles wearers and non-wearers, which can be useful for astronomy visual observation. I know which one of the two fits me better.