Why do my eyes turn red?

Increased blood flow: Because the surface of the sclera (the white part of your eye) is thin & translucent it appears red when blood flow is increased. Blood flow increases to the cornea with infection, irritation, or allergy. It also increases with autoimmune diseases affecting the eyes. Persistent redness of the eye, especially in the presence of pain or eye discharge, requires a doctor's prompt evaluation.

Conunctival redness: The sclera is white. It is never an other color (normally). The covering of the sclera is the conjunctiva which has vessels. It is these vessels that become dilated in inflammation or conjunctivitis. The cornea is avascular and gets oxygen from the air, tears, etc. If something is irritating the eye, the conjunctival vessels become dilated, and the eye will appear red. Depends on the cause!

Many possible causes: There are many causes of redness of the eyes. Several types of inflammatory conditions, allergic reactions, detergents, chemicals, and sometimes bacterial, viral or fungal infections can cause redness of the eyes. Have it evaluated by a professional and get the appropriate treatment.