A blood red eye can be quite alarming when it suddenly greets you in the mirror one morning. Fortunately, most of the time it will turn out to be much less serious than it seems. The white tissue at the front of the eye is known as the sclera. Above this is a thin, clear, transparent layer that is loosely attached to the sclera, the conjunctiva. Because the connection is so weak between the layers, there is potential empty space. There are small blood vessels running through this tissue and they can be somewhat fragile. If a blood vessel breaks, the blood will spread out and fill the empty space. It will often cover a large portion of the white of the eye with a blood-red appearance. These are known as subconjunctival hemorrhages.

A number of problems can lead to these eye bleeds.

• Mechanical trauma to blood vessels can cause them to rupture. Simply rubbing your eyes can be enough force to break the tiny blood vessels in the eye. A foreign object or a blow to the eye is a frequent antecedent. Sports like basketball, where fingers frequently end up in one eye, can certainly give you a ruptured conjunctival blood vessel. Protective sports eyewear can prevent these incidents and many more serious eye injuries.
• Centripetal force or the feeling of weightlessness occurs in roller coasters, merry-go-rounds, bungee jumping, flying maneuvers, and extreme sports of all tastes (intentional or accidental!). Blood flow increases to the head and the increased blood volume can cause a blood red eye.
• Anything that increases the resistance to drainage of blood in the blood vessels is frequently found in the history of subconjunctival hemorrhages. Coughing, vomiting, and even straining with constipation can temporarily increase the resistance to blood drainage in the fragile capillaries of the eye tissues. Lifting weights while holding your breath and even in labor can alter blood flow in your veins.

If you develop a bloody-looking eye, you should seek immediate attention from your optometrist. Rarely there may be other problems that require intervention. Blood problems and diseases can cause recurrent bleeding. People who take blood thinners, regular use of aspirin, and some other medications are at increased risk of bleeding from blood vessels. Some forms of eye infections will cause numerous bleeds, and often in both eyes. Conditions such as diabetes and high blood pressure can make the eye more susceptible to blood vessel ruptures.

Usually the cure is time. These conjunctival hemorrhages will follow a course similar to a skin bruise and will often take three to six weeks to resolve. They will also undergo color changes from bright red to purple before fading. This is an eye condition where the appearance is thankfully much worse than the result!