Reader's digest have an article outlining several ways to improve your vision. Most of the tips mention foods you can eat. Here is a summary of the tips:-

• fresh blueberries + yogurt or bilberry (blueberry) jam
• spinach
• red onions instead of yellow ones
• multivitamin
• sweet potatoes
• beets
• southern greens

• aim car vents at your feet not eyes
• move computer screen to just below eye level
• turn down the heat in the house
• sniff jasmine, peppermint or vanilla
• use eye makeup remover every night
• replace mascara every three months