I must seriously tell you that it is so easy to get eye itchy because of tiredness. The reasons are not far to seek. Firstly, when you stare at something or read something for a long time, pain may occur gradually. Then you start to feel uncomfortable in your eyes. Secondly, the nerves that govern your movements, especially eye movements need to take a good rest. Just like human beings who constantly use brains or work all the time are easily to be fatigue. Then it is time to rest. When nerves are tired, they will "strike", that is, you may see something unclear and you cannot receive the signal of images. Thirdly, you should think over if you have any basic eye problems. Red eyes, pink eyes and glaucoma are possible to cause eye to be itchy. In addition, black eyes are most commonly factors to get eye itchy. All in all, itchy eyes have no unstable causes. You'd better visit an oculist to determine your root reasons for them.