Yes, it is possible for you to get blindness because of crying too much. Once you cry a lot, your tear gland system will work in disorder. Your eyes may be dry seriously which will cause the damage of the visual nerves. That is the main reason to cause the blindness of the eyes. Thus you'd better not cry a lot which will be so bad for your eyes.
Crying too much can weaken the body's resistance to disease, if you don't stop rubbing the eyes, it will cause the slight wound of cornea and suppurative keratitis, and finally bring about corneal ulceration, thus affecting the sight of eyes. What's more, when you cry over and over again, you are likely to lose your vision and get blindness.
Well, as we know, appropriate crying is good for our health. However, excessive crying certainly is harmful for our eyes. I believe you have such an experience that crying too much, your eyes will swollen and pain. In fact, if you crying too much, it will destroy the balance of your body. As a result, your eyes would difficult to recover. So it will affect on our eyes if crying too much.