Red eye can be due to various causes.
In case your eye has burning sensation - it's due to dry eye. It usually goes away with use of over the counter lubricants.
In case you have a lot of itching - it's allergic conjunctivitis. Mild cases resolve on their own, avoid rubbing your eyes.
WHEN TO SEE AN OPHTHALMOLOGIST -
If along with redness your eyelids stick together after waking up from sleep - it's an infection, this needs a ophthalmologist consultation.
If you have pain, blurred vision & when the redness is not reducing despite preventing measures like dark goggles/ lubricants.
Next Steps
Avoid eye rubbing, avoid using computers/ smartphones for a while, avoid going outdoors/ dust/ sunlight.
Health Tips
Use dark googles/ use over the counter lubricants. See an ophthalmologist in the above mentioned situations.