Definition: A visual occurrence characterized by seeing light without having light actually enter into the eye. The most common phosphenes are pressure phosphenes. Rubbing the closed eyes stimulates the cells of the retina. The optic nerve translates this pressure into various images. Pressure phosphenes can remain for a few seconds after the rubbing stops and the eyes are opened, allowing the phosphenes to be seen.
Another common phosphene is "seeing stars." Sometimes a person can see flashes or spots of light from a sneeze, a heavy cough, a strong blow to the head or low blood pressure (such as after standing up too quickly.)
A person may also see flashes or lines of light prior to a migraine headache. These types of flashes are usually caused by a spasm of blood vessels in the brain. These light flashes or lines can also occur without a headache. In this case, the light flashes are called an ophthalmic migraine, or a migraine without a headache.
Less commonly, phosphenes may be caused by certain diseases of the retina and the nerves.
Also Known As: Seeing stars
Alternate Spellings: Phosphine
