Believe it or not, the vitamins, nutrients, and supplements we get in our everyday diets play an important part in our eye health. For example, the omega-3 fatty acids which you get from fatty fish (salmon, tuna, etc) flaxseed, or nuts are important in keeping the oil glands in the eyelids healthy and productive. This helps prevent tear evaporation and dry eyes. Several studies have also shown an inverse relationship between advanced macular degeneration and the omega-3 fatty acids: this means the more omega-3s in our diets, the less risk of macular degeneration getting worse and vision decreasing.
Another example are the anti-oxidant vitamins: vitamins A, C, and E have been shown in many studies to help prevent the progression of macular degeneration in patients at risk. Both lutein and zeaxanthin are also very important vitamins (carotenoids) in controlling the risk of macular degeneration as they have been identified within the macular pigment in our retinas. Macular degeneration, unfortunately, is the leading cause of blindness in the elderly and is expected to become even more prevalent. Lutein and zeaxanthin can be found in dark, green leafy vegetables.
A very informative web-site on these and many more vitamins, minerals and nutrients can be found here. The National Eye Institute has released studies on lutein, zeaxanthin, and omega-3 fatty acid supplements, please visit this website.