There are the tales and warnings that we all heard from a young age about sitting too long in from of a computer screen or sitting too close to the television. Some parents would tell you that your eyes would get stuck in the same position while others would focus on the fact that this might mean that you would need to get glasses by the time you were grown up. For the most part, this is an exaggeration of what a screen can do to your eyes. But that doesn't mean that it doesn't have any effect on you. What can happen is you can develop eye strain.
Eye strain comes from your eyes getting overly tired from any intense use. This could mean that you're working at a job that forces you to stare at a computer for eight hours a day or could be the result of driving back to your home from a trip up north for eight hours without much stopping. The main symptom that people experience with eye strain is that their eyes become sore and tired. They might be itchy and can either water or become very dry. You could also get temporary blurred vision and some people might become sensitive to light. If the strain is coming from the light of a screen rather than natural light, then you might also see color fringes or have trouble going from the light to seeing out normally.
It is also possible that your dry and itchy or watery eyes can be a result of your something in your environment rather than something you are doing with your eyes. For example, certain types of mold can cause mild but serious symptoms with extended exposure. Might be something to consider if your eye discomfort only troubles you in certain locations.
Most eye strain will go away on its own once you have the chance to rest your eyes but there are some times when it can become severe and you will want to see your doctor about it. You should do this if you notice that there is a change in your vision that is lasting quite a while after you are done working on that work website or watching television. You could also have headaches that are lasting for an extended period of time or double vision.
The most common causes of eye strain are looking at a screen for too long, reading in too low a light, exposure to bright light, and any activity that forces you to stare at the same spot or general area for a long period of time. Sometimes you can solve the problem by no longer doing the thing that causes your eye strain. But if you're working in an office or with a strapping machine that you need to focus on all day, then you should just try to take a break every once in a while for fifteen minutes to allow your eyes to relax and readjust to your surroundings.