Why do some people sneeze when they walk into bight sunlight?

Some people sneeze in bright sunlight due to a reflex known as the photic sneeze reflex. This occurs when bright light stimulates the optic nerve, which can inadvertently trigger the sneeze reflex in some individuals. It's thought to be a genetic trait, affecting an estimated 10-35% of the population. The exact mechanism is not fully understood, but it demonstrates how our sensory systems can be interconnected.