All right, looks like eye health is of great importance to you, that is good news actually. So, from what I know, our tear ducts would automatically produce lots of tears when they are irritated, but since those tears are made up of a lot of complicated contents in your head, they would simply not get dried. And your eyes would be ok, except some red eyes and swollen eyes. So you'd better try not to do that.
Yes, tears will run out one day if you keep on crying. The excessive crying will make the tears gland system work in disorder. At the same time, your eyes will easily be dry. It may also cause other eyes problems, like pink eyes because of the coming invisible bacterium which you should take notice of. You'd better not cry which will also affect your mood and your health.
Well, there is no doubt that too much tears out of eyes would cause eye dry and eye strain. Although tears can moist the surface of eyes, they still can flush away many benefical things in eye if they do not work in normal way. However, dry eye cannot have one cause. Working at the front of computer in a long time, staring digital screen constantly and stay up may be all possible to contribute to dry eye. But you can take easy because dry eye is not an eye disease, it is just a sign of eye diseases. Drop some basic eye drops and drink too much honey water, or eat some fresh fruits everyday can alleviate your pain, dryness and irritation in eyes.