I've seen an ad on tv recently about "eyes losing vital nutrients as you age." I don't recall what the product is called, but I do remember the 3 key ingredients:
Lutein (a carotenoid)
Zeaxanthin (a carotenoid)
Omega-3s
Thus, I would advise you to pick up foods containing high amounts of carotenoids and Omega-3s. Examples are carrots, sweet potatoes, dark leafy greens (kale, spinach, turnip greens and mustard greens), tomatoes, and other orange and red veggies.
For omega-3s, I advise o3-enriched dairy, o3-enriched eggs, edamame (soy), wild rice, walnuts, canola oil, flaxseed, beans, and seafood.
Along with this suggestion, water and exercise can only help. Don't feel like exercising? Practice posture and walk more. Also try to keep track of your electrolyte intake - potassium and sodium can do wonders for your system if taken in correct amounts. I take the lazy way and go with Gatorade.