Well, I mean, do you really have to focus your vision on one particular thing for much too long? So, as a matter of fact, if you insist on trying to experiment with your eyes, you will experience some feelings of blurry vision, vertigo, dizziness. However, this would not give you some deadly consequences. However, you need to take care of your eyes, not abuse them.
If you stare at one thing for a long time, your eyes will be blurry. You'd better not do this because your eye nerves will be intense. If you do this often, your eye vision will be affected. You should often get relax for your eyes. Then you will find that you have the good vision. Staring at one thing for a long time will be bad for your eyes.
Of course, it can lead to eye strain. So you are not supposed to do thing like that. Generally speaking, it is easy for you to have eye strain, if you stare at something for a long time. And also, it can lead to other effects. For example, it can put stress on the eye muscles and the facial and scalp muscles, and then it turns to pain and headache. And if you do it for many times, it can lead to worse vision. And also, it can lead to some eye diseases, such as the dry eyes, blurred vision, even red eyes. Anyway, just avoid it.
When fixing eyes on an object for long, people may lose visual focus. Doing this one time or two do not cause any problems. However, it is not recommended to do lie that all the time as the eyes will get tired easily. For an eye patient or people overusing their eyes, however, the stare may result in serious problems, such as eye ache, headache, or nausea. At the present days, people will use PCs in working, fixing eyes on a PC is inevitable. We should take a short break intermittently and have some vegetables and fruits rich in vitamins A and C, for example carrots and pears.