It is very important to own the vitamin a for the body. When we lack the vitamin a, our eyes may get twitching. Vitamin a lack for the body may have a lot of side effects. Lack of vitamin e can cause visual problems, muscle problems, hair normal growing problems, skin problems and so on. What's worse, it can even cause the dry skin which you will feel uncomfortable at the whole body. The lack of vitamin A will cause the systemic symptom. Your skin will be dry and you will have loose elasticity. You may even get the hoarse voice. There may be the intercurrent infection development for the panophthalmitis which may cause the blindness. Then your eyes will feel the uncomfortable state. The eye nerves will be affected, not working in normal state. The eyes are easy to be infected by the outside invisible bacterium. Then the eyes can't help start twitching.