OK, I can see that you suffer a lot from dry eyes and as a matter of fact, it could be resulted from various causes. So, you should try to figure out what led to it. And actually, vitamin D indeed could help with your dry eyes, along with vitamin A, they could help your eyes keep healthy and in good conditions because they are necessary for your eyes. Maybe you can get some vitamin pills and more vegetables.
Unfortunately no, it could not help with dry eye. Dry eye means there is no sufficient tears that are produced by the gland in the eyelid, thus your eyes would not have enough moisture. Vitamin D, especially vitamin D3 is a necessary nutrient for helping your body to absorb and use calcium properly. At the same time, it can assist your body to fight bacteria and viruses. However, dry eye is not caused by any bacteria or virus, so that it could not likely help dry eye. The best way for treating dry eye is using artificial tears to keep your eyes lubricated.
Dry eyes are most commonly caused by tears reducing, that is, glands in your eyelids produces tears which are much less than normal. Meanwhile, if glands in eyelids cannot produce quality tears, dry eyes may also occur. I seek deeply online and found that vitamin D is not likely to help dry eyes because vitamin D is good for proper muscle and nerve functioning, even help to fight bacteria and viruses. However, dry eyes is hardly to be caused by bacteria and viruses. Well, the best way to heal dry eyes is to call a doctor for help. If you wanna heal it through supplements, then doctor's advise are very important. My elder sister, a doctor, who said that salmon, walnuts and fish is good for individual dry eyes.