Phosphenes can be triggered by various stimuli, such as gently rubbing your eyes or receiving a sudden blow to the head. These actions apply pressure to the retina, the light-sensitive layer at the back of the eye, which can cause the sensation of seeing light or patterns. Interestingly, phosphenes can also be induced by electrical stimulation of the visual cortex, the part of the brain responsible for processing visual information. This discovery has opened up exciting possibilities for the development of visual prosthetics, offering hope to individuals with certain types of blindness.
But how exactly do phosphenes work? The answer lies in the retina’s photoreceptor cells, known as rods and cones. These cells are primarily responsible for detecting light, but they can also be activated by mechanical or electrical stimulation. When the retina is stimulated by pressure or electrical current, it sends signals to the brain that are interpreted as light or patterns, resulting in the captivating display of phosphenes.
Phosphenes can take on various forms, from simple flashes of light or stars to more intricate patterns and shapes. They can appear in different colors, often white, gray, or yellow, but sometimes also in vivid hues of red, blue, or green. These ephemeral visions typically last only a few seconds to a few minutes, adding to their enigmatic nature.