• The best vitamins for eye health include vitamin A, vitamin C, vitamin E, and B vitamins.
• Vitamin C may help protect against cataracts and slow the progression of age-related macular degeneration (AMD).
• A deficiency in vitamin A can harm the cornea and retina, which can damage your vision. 

In many cases, eating a balanced diet with plenty of fruits and vegetables is enough to keep your eyes healthy. But if you suffer from certain serious eye diseases, you may also need to add in vitamin supplements.

Here are 4 of the most important vitamins you need to keep your eyesight sharp.

1. Vitamin A

"We've all heard that carrots are good for the eyes. This is in part because they have high levels of vitamin A," says Sunir J. Garg, MD, a Professor of Ophthalmology at Thomas Jefferson University.

This is because vitamin A helps produce the pigments that allow your retina to work properly. When you don't have enough vitamin A, you may have trouble seeing in low light.

"Thankfully this type of vision loss can often be improved when vitamin A levels go back to normal," Garg says. This means you likely don't need a huge boost of vitamin A, as long as you are getting the recommended daily value, between 0.7mg and 0.9mg.

Here are some foods that are rich in Vitamin A: 

2. B vitamins

B vitamins — like B6, B12, and folic acid — can help improve eye health by preventing age-related macular degeneration (AMD), a condition in which your retina deteriorates over time, causing blurry vision. This is because B vitamins reduce your blood levels of homocysteine, an acid that can affect the arteries of your retina and is an independent risk factor for AMD.

A deficiency in B vitamins can also lead to problems with the optic nerve, the tissue responsible for taking the images from the eye to the brain. In severe deficiency, it can cause reduced vision or blind spots. 

Here's how you can get more Vitamin B6, a crucial B vitamin: 

3. Vitamin C

Cataracts, the cloudy areas that develop on the lens of your eye, are among the most common reasons your vision can get worse as you get older.

Antioxidants help protect against free radicals that can cause changes to the lens in your eye, leading to a cloudy appearance that disrupts your vision.

Several studies have shown that getting at least 40 mg per day of vitamin C (for reference, the recommended value is 60 to 90mg per day) can help prevent cataracts from developing. But be careful not to get too much, since a very large 2013 study found that getting over 500mg of vitamin C may actually increase the risk of cataracts for certain groups, like men who are smokers or obese.  

Studies also show that vitamin C can also help slow the progression of AMD by strengthening the blood vessels in your eye that support the retina. A 2016 study found that people with higher intake of vitamin C were significantly less likely to suffer from AMD.

4. Vitamin E

Vitamin E also acts as an antioxidant in your body and studies show that it may protect you from vision loss in old age.

More research is needed, but some studies suggest that eating a diet rich in vitamin E or taking vitamin E supplements over a long term may help prevent cataracts and AMD.

A 2005 study found that people who took vitamin E supplements were less likely to develop cloudy eye lenses over the course of 5 years. However, a 2001 study found that taking a daily 400 IU vitamin supplement had no effect on eye cloudiness.

Some foods that are rich in vitamin E include:

Takeaways 

Getting enough of these important vitamins in your diet can go a long way towards strengthening and protecting your eyesight. In most cases, you likely won't need to take additional supplements unless you have a vitamin deficiency.

"For most people, the amount of these vitamins that we get from a well-balanced diet is plenty," Garg says.