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.)
