- Subconjunctival hemorrhage: The red spot you see is most likely a small blood vessel that burst open. In medical terms, it is called a subconjuntival hemmorhage. Small blood vessels lie underneath the conjunctiva, the clear coating that covers the sclera, the white part of the eye. When one of the vessels breaks open, the blood has no place to go but underneath the conjunctiva. If a larger blood vessel bursts open and bleeds, it can be quite startling when you look into the mirror. In some cases, the blood can spread out over the entire white part of the eye. These hemorrhages can be caused from trauma, constipation, straining too hard, lifting something too heavy, diabetes, or hypertension.
- Episcleritis: Episcleritis is an acute inflammatory disorder of the episclera, the thin tissue between the conjunctiva and the white sclera. The episclera houses a thin network of blood vessels. Episcleritis usually looks much worse than it actually is. Although most cases of episcleritis go away on their own, about one-third of cases are linked to hidden inflammatory problems present elsewhere in the body.
- Sickle cell disease: Sickle cell anemia is an inherited blood disorder that is characterized by chronic anemia and intermittent pain. It is caused by abnormally shaped blood cells that have difficulty transporting hemoglobin and oxygen throughout the body. Sickle cell patients will sometimes display comma shaped red spots or lines on the white part of their eyes. This is due to the sickling of red blood cells within small vessels, leading to tiny blockages.
- Pinguecula: A pinguecula is a common growth or thickening of the tissue that lines the outside of the eye. It can appear elevated and yellow in color. You may be unaware that you have a pinguecula, but if you spend several hours in the sun and wind, it can become inflamed. When it is inflamed, it is referred to as pingueculitis. It can become red and swollen and suddenly appear on your eye. A pinguecula is thought to be caused by ultraviolet sun radiation or chronic irritation.
- Conjunctival hemangioma: A conjunctival hemangioma is a congenital malformation of a clump of tortuous blood vessels that sometimes develops on the white part of the eye. A conjunctival hemangioma is usually benign, but some people become concerned about their cosmetic appearance. They should be examined annually and if the patient desires, they can be surgically removed.
- Benign and Cancerous Growths: Keratoacanthoma, actinic granulomas and conjunctival epitheliomas are growths that can be serious. If you notice any new growths on the surface of your eye, see your eye doctor as soon as possible.
Catania, Louis J. Primary Care of the Anterior Segment, Second Edition. Appleton & Lange, 1995.