Vitamin A
Vitamin A is otherwise known as retinol, which is an intermediary to retinal. or beta carotene. When it is in the form of retinal, this metabolite will act as a light absorbing molecule.
Vitamin A is also an essential component of retanoic acid which is a crucial signalling molecule especially during Early Organogenesis [2]
It is necessary for low light and colour vision, as it is found in the retina of the eye. Vitamin A is used in the treatment of Rhodopsin-related diseases.
A defficiency of Vitamin A is known to cause night blindness due to its essential role in the ocular system of the body.
Biochemistry 6th edition international edition by Lubert Stryer Jeremy Berg and John Tymoczko