Zymaxid can be expensive if you don't have health insurance, prices at local pharmacies can vary greatly, but be prepared to pay as much as $100 for a 2.5ml bottle size of zymaxid 0.5 eyedrops.
Vitamin A is critical for vision as an essential component of rhodopsin, a protein that absorbs light in the retinal receptors, and because it supports the normal differentiation and functioning of the conjunctival membranes and cornea [2-4].
Older Age- the skin is less able to convert sunlight into vitamin d. Being very large or obese- you simply require more vitamin d the larger you are. Having Low Cholesterol Levels- cholesterol is required to convert sunlight to vitamin d in the skin. Eating a very low fat diet- vitamin d is fat soluble and you must have fat to absorb it. Having very dark skin- blocks the UV rays from reaching the cells that make vitamin d in the skin.