Roundup is a herbicide. If it infiltrates your eyes, you should go to see a doctor immediately. After consulting a doctor or poison control, the eyelids should be held open and flush eyes with water for 10 to 20 minutes. Also, your contact lenses should be taken out after five minutes of rinsing.
Ok, as you can see roundup is supposed to get rid of the excessive grass in the garden. However, it is made up of chemical toxic things which could impair your eye health, causing some infections and painful eyes. So, you should hurry to get a lot of normal saline to flush your eyes, then try to get eye drops to deal with your problem. If the situation remains bad, a doctor is needed for you.
You'd better put it into relax and protect the eyes from the diet and good sleep. You'd better have the good rest for the eyes. You could go to the hospital to have the full check on the eyes to accept the medical treatment as soon as possible. With the home remedies of some ways to protect the eyes, your symptom will be released soon.