Summarize this article:

Foods rich in vitamins A, C, and E are vital for good vision. Eating plenty of food rich in these three vitamins is a great first step for sharpening your ability to see. You should also strive to eat foods rich in beta-carotene, lutein and zeaxanthin, since these antioxidants protect the eyes from sun damage.  Eat dark leafy greens, pumpkin, sweet potatoes, carrots, and peppers. Blueberries, grapes, garlic, onions, and shallots also contain antioxidants that protect your eyes. Foods with DHA, a fatty acid, are also essential for healthy eyes. Eat salmon, sardines, cod, and mackerel. Having to strain to see what you're doing can hurt your vision over time. Invest in good lighting in your office and home workspaces to avoid hurting your eyes. It's very important to get up and look outside, so that your eyes don't get strained from staring up close at the blinking lights on your computer. Every hour or so, stand up and look out the window. Gaze at an object several miles away, if possible. Keep looking until your eyes adjust to the view. Having dry eyes can cause your vision to look blurry. Drink at least 8 glasses of water every day. If you wear contacts, be sure to clean them properly and change them frequently. Use saline drops as tear replacements if you have trouble producing your own tears. You can sharpen your vision by performing a few simple exercises on a daily basis. Do them when your eyes feel a little tired and you need a break from whatever task is at hand.  Roll your eyes around. Look up, then to the side, then down, then to the other side. Repeat ten times.  Focus on an object. Hold it close to your face, then move it slowly backward, keeping your eyes focused on the item. Move it close to your face again, maintaining focus. Repeat 10 times. Test your peripheral vision. Stand facing a wall, staring straight ahead. Try to identify what is on either side of you using your peripheral vision. Move closer to the wall and keep using your peripheral vision to see from side to side. Continue until your side views are blocked. Repeat every few days, and little by little, you'll gain a greater ability to see what's in your peripheral vision.

Summary:
Eat food that makes your eyes healthier. Make sure you have adequate lighting in your workspace. Don't stare at a computer all day long. Make sure your eyes are moisturized. Do eye exercises.