Red eyes are caused when the small blood vessels on the surface of the eye (sclera) enlarge and become congested with blood. This occurs as a result of insufficient oxygen to the cornea or the tissues covering the eyes. Generally, the reddened eyes aren’t really a cause of major concern, but if pain or impaired vision, it can be an indication of a serious problem. A variation of this condition is a brilliant, bloody, uniformly dense red area that forms in the lens as a result of a small amount of bleeding. This bloody stain usually occurs upon awakening in the morning. Not too bad but it looks horrible, and clears within a few days. John Brown: the source for more info.
This bloody stain is called a Subconjunctival hemorrhage. Diagnosis of reddened eyes if an episode of reddened eyes persists for more than three days or you are experiencing any problem of pain or vision, it is essential that you consult a doctor who determine the cause and help him find relief for red eyes. The cause will be diagnosed by an examination of the eye as well as your medical history. Your doctor may also perform a physical exam to eliminate any other ailment. The degree of redness is not generally correlated to how it is so serious the situation, but your overall health status should be considered. Bloodshot eyes are not usually an isolated symptom and but the result of another condition, and must consider the severity of other symptoms such as eye pain or deteriorated vision. Reddened eyes often occur with other symptoms, including: * pain * itching * swelling * pain of head/neck pain * dry eye * stomach/swelling/pain pain * sneezing / coughing * feet/hands swollen what causes reddened eyes? Common causes of reddened eyes include visual fatigue and mechanical irritation. Environmental factors including exposure to extremely dry air and Sun, as well as allergies, infection, trauma, an improper diet and alcohol consumption they can also contribute to the appearance of reddened eyes.