Fényhangérzékenység

Fényhangérzékenység, also known as photic sneeze reflex or sun sneeze reflex, is an autosomal dominant inherited trait that causes individuals to sneeze in response to sudden exposure to bright light. It is estimated to affect between 18% and 35% of the population.

The exact mechanism behind this reflex is not fully understood, but several theories exist. One prominent theory suggests a misfiring of the trigeminal nerve, which is responsible for facial sensation, including pain and touch, and also plays a role in the sneeze reflex. The optic nerve, which carries visual information to the brain, runs in close proximity to the trigeminal nerve. It is hypothesized that in individuals with this reflex, a strong visual stimulus from bright light might inadvertently trigger the trigeminal nerve, leading to a sneeze.

Another theory proposes that the pupillary light reflex might be involved. When the pupils constrict rapidly in response to bright light, this action could somehow stimulate the nasal mucosa, causing a sneeze.

The reflex is typically triggered by a sudden change in light intensity, rather than just being in a bright environment. For example, stepping out of a dark building into bright sunlight is a common trigger. The number of sneezes can vary from one to several. While generally considered a harmless anomaly, it can sometimes be inconvenient or even dangerous, such as when driving. There is no known cure for the photic sneeze reflex, but individuals can learn to anticipate and manage it, for instance, by wearing sunglasses or gradually adjusting to light changes.