Xác định nguyên nhân gây đau mắt đỏ. Cần biết khi nào nên đi khám bệnh.

I'm interested in that, but I only have a few mins. Can you give me at most the first 500 characters of a detailed explanation in English about that?
Conjunctivitis can occur due to viruses, bacteria, and allergies. All types of pink eye cause the eyes to become red, watery, and itchy, but the other symptoms of pink eye will vary according to its cause.  Viral can affect one or both eyes, and individuals with this condition may experience sensitivity to light and watery discharge. Viral conjunctivitis is highly contagious and difficult to treat. It usually needs to run its course, which can take anywhere from 1 to 3 weeks. The best way to tre