Closing one eye while reading

There are a few possibilities of what is going on for you.

The first possibility is that you are very near sighted and so the point where you see clear is not the same is the point where you see single. You would see clearly very close but not be able to converge, or bring both eyes together, to also see single so you break into two separate images. To get rid of the double vision you would then just simply close one eye (gets rid of one of the 2 images). Then to see clearly you just read with the one eye opened, usually the eye with the smaller prescription. The reason you like your glasses off is because they minify the reading material so you enjoy the magnification of print without the glasses on. This typically occurs with high myopic prescriptions like -6.00 or greater so it is a bit strange that you have such a small prescription and would experience this at -1.75. Also you don’t report double but rather a ghost image.

This brings me to the more plausible second possibility. A prescription of -1.75 is one of those perfect prescriptions for reading where you can very comfortably read at a standard working distance without glasses! But the only wrinkle is that you have a moderate difference in prescriptions between your eyes and you see two different image sizes without your glasses, one for each eye. So you close the eye with with the more smeared and blurry image and you comfortably read with the clearer seeing eye without glasses. In this scenario you should be able to see clear and single with your glasses on.

A final possibility is that you have a binocular vision problem. This is where you prefer to read without glasses on and you have relatively similar prescriptions between the eyes but have difficultly with converging your eyes or bringing them together up close so the image breaks into a smear, where they’re slightly separated but not quite double. This is treatable. In this scenario you should be able to see clear and single with your glasses on and holding the print further out from your face.

Regardless of the scenario, reading with one eye opener doesn’t damage your eyes, you are simply enjoying reading with that one perfect eye prescription without the other eye interfering. You may experience eye strain from having the single opened eye focusing your close all the time.

The final thing to note is that any new-onset sudden double vision that you can’t get rid of by putting your glasses on is not normal and should be checked out!

/r/eyetriage Thread Parent