The term “red eye” can refer to a nighttime airline flight, Red Eye, Minnesota, Red Eye energy drink, Red Eye gravy, a photograph in which light from the flash bounces off the retina and back into the camera, and much more. It is also the name of an eye condition similar to “pink eye” but far more common.
Many of the above are so named because they supposedly can or have caused the eye condition “red eye” (except for the camera flash)..
Red eye occurs when the blood vessels of the conjunctiva (that little piece of meat in the inner corner of the eye) and sclera (the white of the eye) become inflamed. The condition is called hyperemia or vasodilation, which increases blood flow.
Diseases or conditions in which red eye is a symptom include conjunctivitis, blepharitis, glaucoma, hemorrhage, pterygium, high stress, drug use (especially cannabis) and dry eye disease. If accompanied by symptoms such as eye pain or blurred vision, red eye can be a red flag indicating a more serious problem.
A common remedy for simple red eye that is caused by stress and fatigue, is the application of an over the counter “redness reliever.” These are vasoconstrictors similar to nasal decongestants. A pure water moisture mist will also soothe and relax red eyes, especially if caused by stress, fatigue or dry eye.