To care for your eyes, you must be a healthy weight. Obesity leads to diabetes which can create great damage to your eyes. It also leads to glaucoma, hypertensive retinopathy and other conditions which can lead to blindness. The healthier your body is, the healthier your eyes will be, so lose weight!
Do you wear contacts? If so, make sure you have a pair of glasses that you can wear if your eyes get irritated. You do not want to make the situation worse by forcing yourself to wear the contacts because serious problems can result. Also, make sure you keep the contacts very clean.
While sunglasses are helpful for protecting your eyes from the sun's UV rays, it may also be wise to wear a wide-brimmed hat. Wearing this kind of hat prevents any UV rays from reaching your whole face, including your eyes. So, if you know you will be outdoors for a long period of time, wear this kind of hat.