My optician told me spending long hours (in dark or sunlight) in front of a television doesn't make your eyesight go bad. It's a common myth. The main reason is simply aging.
I heard eye drops are sometimes needed because you blink less when staring at code. Personally I've never used them.
While that permanent damage is still contested, its true that your eyes can become strained and sore from focusing on a single distance though, so you should still take regular breaks to avoid discomfort, even if there isn't permanent damage. Also the lens of your eye can become weaker and make focusing on further objects harder. There are eye exercises that are mostly centered around alternating focus on near and far objects you can do to stretch the lens.
A very simple exercise to to take something small that has writing on it like a pencil and find something else that is about 10 meters away and also has writing on it and go through the letters on the smaller object while alternating focusing on the far object between each letter. You can do this a few times, moving the small object closer to your face each time. You will feel your eyes get tired very quickly if they are out of shape.
