Vitamin protects the surface of the eye (cornea), and it is essential for good vision. Vitamin A eye drops are effective for the treatment of dry eyes, superior limbic keratoconjunctivitis, macular degeneration (AMD). It also appears that a combination of vitamin A and lutein may prolong vision in people suffering from retinitis pigmentosa. One of the first signs of vitamin A deficiency is night blindness. Lack of vitamin A causes the cornea to become very dry, leading to clouding of the front of the eye, corneal ulcers and vision loss. Vitamin A deficiency also causes damage to the retina, which also contributes to blindness. Because vitamin A also is important for resistance to infection and a healthy immune system, vitamin A deficiency can lead to death from respiratory and other infections.