You likely have a subconjunctival hemorrhage. This happens when delicate blood vessels of the conjunctiva (clear covering of the eye) burst. This is very similar to a bruise, but redder because there is no skin overlying the blood. The bleeding is usually the result of minor trauma such as coughing or eye rubbing.Though its appearance is alarming and appears dangerous, it is generally harmless.Similar to a bruise, subconjunctival hemorrhage may take 1-2 weeks to reabsorb and go away. During that time, it may darken and change colors. That is expected and no need to worry. Worrisome symptoms are pain, decrease vision, or double vision. You should contact your ophthalmologist promptly if these occur.