Well, generally speaking, if your eyes do not make enough tears to coat the eye, you may have dry eye. And according to some experts, there are many factors which can lead to dry eyes, including vitamin a deficiency. For example, if you do not intake enough vitamin A, you may also experience problems with dry eye. Besides, if you have dry eyes, you may experience scratchiness, itching and burning on the surface of your eyes. So anyway, it can be dangerous. On the other hand, Blephariti is inflammation and it occurs on the part of the eyelid where the eyelashes grow. Because of it, your eyes can eventually become red, irritated and itchy. And when the small oil glands near the base of the eyelashes don't work properly, it can be possible too. And when it occurs, double vision and blurred vision may occur too, so just be careful about it.
In fact, dry eye and blepharitis are totally different eye problem. Usually, blepharitis is caused by allergic reaction and an an infestation of lice on the eyelashes. And people with blepharitis usually have redness and swelling along the edge of the eyelids. But dry eyes usually caused by the a lack of adequate tears. And this condition may result of natural aging process, especially menopause or taking of birth control pills. And people with dry eyes may feel uncomfortable, dry and itching in the eyes. But they won't cause swelling eyelids.