Coughing forcefully can sometimes lead to the surprising sensation of “seeing stars” or flashes of light. This temporary visual phenomenon, while startling, is a common experience for many people. It often resolves quickly and is generally considered harmless.
Understanding Phosphenes
The “stars” or flashes of light you perceive without actual external light entering your eye are known as phosphenes. These visual impressions occur when the retina or optic nerve is stimulated by something other than light itself. Phosphenes can appear as bright flashes, dots, squiggles, or colorful patterns. They are a type of photopsia.
Mechanical stimulation, such as rubbing your eyes, is a common way to induce phosphenes. The pressure on the eyeball activates the photoreceptor cells in the retina, causing them to send signals to the brain that are interpreted as light. Other everyday actions, like sneezing or a sudden blow to the head, can also trigger these temporary light perceptions.
The Mechanics of Coughing and “Stars”
A forceful cough creates a sudden increase in pressure within the chest and abdomen. This elevated pressure can briefly impact blood flow to the brain and eyes. When blood flow to the retina or optic nerve is temporarily reduced, or when pressure directly affects these structures, it can lead to phosphenes.
The transient air pressure inside the head during a cough can briefly press the eyes against the eyelids, stimulating peripheral vision and causing false signals down the optic nerve. Additionally, pressure changes can cause the vitreous humor, a gel-like substance in the eyeball, to pull slightly on the retina, triggering light sensations.
When to Seek Medical Advice
While seeing stars after coughing is usually harmless and temporary, there are instances when it warrants medical attention. If the “stars” or flashes of light persist, become more frequent, or are accompanied by other concerning symptoms, it is advisable to consult a healthcare professional.
Specific red flags include a sudden increase in eye floaters, which are small specks or strands that drift through your field of vision, or flashes of light that occur without coughing. Other symptoms like vision loss, a curtain-like shadow appearing in your vision, or if the flashes are accompanied by dizziness, headaches, or fainting, also indicate a need for prompt medical evaluation. These could signal a more serious underlying condition, such as a retinal tear or detachment, which requires immediate attention to prevent permanent vision loss.