It sounds like the first thing you need to do is see an eye specialist
(either an ophthalmologist or optometrist
) for a thorough eye exam. It is not unusual for people who spend their day looking at small print, either on paper or a computer screen, to suffer from some degree of eye strain or fatigue at the end of the day. This can often be corrected or alleviated with contacts or glasses if you have developed a mild change in your visual acuity, thus preventing your eye muscles from having to "strain" all day in order to allow you to read properly. However, the fact that your eyes are improving with sleep also suggests that you might be suffering from dry eyes during the day which can also contribute to the sensation of eye fatigue, often accompanied by a "gritty" feeling by the end of the day. Dry eyes can be benign and an entity that occurs independently, in which case eye drops or even sometimes minor ophthalmology office procedures can help prevent tear loss during the day. However, dry eyes can sometimes be a sign of underlying processes, including some autoimmune diseases such as Sjogren's syndrome. For this reason it would be a good idea to be evaluated by a physician just to make sure everything else is fine with your health and current symptoms.