When you close your eyes, you may notice an array of colors, patterns, or flashes. This common visual phenomenon is known as phosphenes, perceptions of light without an actual external light source. This is generally a normal occurrence. These intriguing displays can range from subtle glows to more vivid, swirling shapes.
The Science of Seeing Light Without Light
Your visual system does not simply deactivate when external light is absent or your eyelids are closed. Even in complete darkness, the cells within your retina maintain spontaneous activity. These cells continue to generate low-level electrical signals.
The brain interprets these inherent internal signals as perceptions of light or color. This interpretation occurs in the visual cortex, which processes visual information. The colors and patterns you see are the brain’s processing of inherent activity within your ocular system.
Everyday Triggers of Closed-Eye Colors
Common actions can induce phosphenes. Applying pressure to the eyes, such as gently rubbing your eyelids, stimulates retinal cells, leading to the perception of light or color. This explains why you might “see stars” after pressing on your eyes, or from actions like coughing or sneezing that temporarily increase pressure.
Residual light also plays a role in generating these internal visuals. Light can penetrate through closed eyelids. After exposure to bright light, the retina may retain a “memory” of the light, causing afterimages or faint colors to appear when your eyes are closed.
Prolonged darkness can heighten the retina’s sensitivity, leading to an increase in spontaneous cellular activity. This adaptation to low light conditions can result in more noticeable phosphenes as your visual system becomes more attuned to any internal signals.
When to Be Concerned
While most experiences of seeing colors with closed eyes are normal, certain visual phenomena can indicate an underlying eye condition. If you suddenly experience new, persistent flashes of light, especially if they occur repeatedly, or a significant increase in “floaters” (small specks or squiggly lines drifting in your vision), it warrants attention. These symptoms can be distinct from the fleeting, diffuse colors of typical phosphenes.
These particular symptoms, including a sudden shadow or “curtain” obscuring part of your vision, could signal a retinal tear or even a retinal detachment. A retinal detachment is a serious condition where the retina pulls away from its supporting tissue, potentially leading to permanent vision loss if not addressed promptly. Should you experience any of these concerning symptoms, it is advisable to seek immediate medical evaluation from an eye care professional.