Research: Up to 35% of the world’s population sneezes after seeing bright light

August 31, 2023

Do you sneeze after seeing a bright light? Well, you’re not alone. In fact, according to researchers, 18%–35% of people worldwide are shining examples of what has jovially been labeled the ACHOO syndrome, reports My Modern Met.

Clinically known as the Photic sneeze reflex—and also, in popular usage, as autosomal dominant compelling helio-ophthalmic outburst (ACHOO syndrome)—the condition is characterized by successive sneezing induced by bright light. This is different from a normal sneeze, which is triggered by an infection or an irritant.

According to findings of a 1995 study, published in the Journal of the American Optometric Association, the majority of photic sneezers are female and white.

According to Scientific American, when those affected by the syndrome emerge from dim light into sunlight—or turn to face directly into the sun—the glare commonly triggers the sneeze reflex. The number of induced sneezes—which seems to be genetically mediated and can be predicted within a family—is constant from episode to episode and typically numbers two or three.

Records of ACHOO syndrome have been found as far back as 350 BCE. Unlike regular sneezes, which occur after the mucous membranes in our nose are irritated by particles, there is no physical trigger other than bright light. This can happen outdoors in the sunshine, or inside after turning on the light. “The reflex seems to be triggered by a change in intensity of light rather than a specific type or wavelength of light,” Dr. Annie Nguyen, an ophthalmologist with Keck Medicine of USC, says.

Although scientists know that ACHOO syndrome is genetic, they are still unsure what causes it. One previous theory suggests that bright light which makes the pupils constrict also irritates the nose. Another proposes that it’s due to higher sensitivity to visual stimuli.

Research contact: @mymodernmet