Well, generally speaking, there are various factors that can play into why you are experiencing red eyes. And of course, it will be beneficial to learn what you can do to relieve the symptoms and prevent them from returning. And in common, redness in eyes could be due to an illness, injury, eye infection, or other condition such as allergies. And also, it's a very common condition and usually relates to something else such as tiredness, substance abuse, allergies, cold or trauma. Of course, dry eyes can also lead to it too. So in my opinion, for your situation, you need to go and see the eye doctor, and he can just give some exam.
Your redness of the eyes may be caused by the infection from the invisible bacterium. When your eyes don't feel itchy or painful, your infection doesn't get that serious. You need to treat it as soon as possible. You could use the eye drops to release the redness of eyes. You could also use warm compress to release it.
At first, did you either stay up last night or stare at the PC or TV screen for entertainment for a day long? If so, I assume that you may suffer eye fatigue which can be caused by being highly concentrated on something leading to reduced eye blinks and insufficient tearing. In a healthy eye, the sclera is essentially white with a few small blood vessels visible. But if there is an inadequate tear film, you eyes may not feel discomfort at once, but as long time accumulated, you will inevitably feel itchy, pain, or discharge. Rest you eyes. Next, you are recommended to look at the mirror to see if there are any foreign stuff in your eyes, and really roll your eyes to see if there anything come out of your eyes due to some of the tiny dust floating in the air may not be irritated. Finally, see a doctor if it does not get better later.