The sensation of seeing little lights when you sneeze is likely caused by pressure changes affecting your eyes and visual cortex.
Explanation of Phosphenes
These lights you see are called phosphenes. Phosphenes are visual sensations of light caused by something other than light entering the eye. In the case of sneezing, it's generally due to one of two mechanisms:
-
Pressure on the Eyes: When you sneeze (or cough vigorously), you tend to squeeze your eyes shut. This applies pressure to the eyeballs. This pressure stimulates the retina, the light-sensitive tissue at the back of your eye, which then sends signals to your brain that are interpreted as light. It's a similar effect to what you might experience if you gently rub your eyes. The reference text also mentions that rubbing your eyes can cause you to "see stars" due to the pressure applied.
-
Pressure Changes and the Brain: The act of sneezing dramatically increases pressure within your body, including in your head. This pressure surge might affect the visual cortex, the part of your brain that processes visual information, leading to the perception of phosphenes.
Why It's Usually Harmless
Seeing phosphenes when you sneeze is usually harmless and temporary. It's a normal physiological response to the pressure changes involved.
When to be Concerned
While generally benign, consult a doctor if:
- You experience phosphenes frequently without sneezing or other obvious triggers.
- The phosphenes are accompanied by other visual disturbances, such as blurred vision, floaters, or flashes of light.
- You experience headaches, dizziness, or other neurological symptoms along with the phosphenes.
In these cases, it's important to rule out any underlying medical conditions.
