Why do we sneeze when we look at the sun

The phenomenon of sneezing when exposed to bright light, such as sunlight, is known as the “photic sneeze reflex“ or “ACHOO syndrome“ (Autosomal Dominant Compelling Helio-Ophthalmic Outburst syndrome). It's estimated that about 18-35% of the population experiences this reflex. The exact reason for this response isn't entirely clear, but there are a few theories: 1. **Nerve Cross-Talk:** One theory suggests that there might be a cross-wiring or cross-activation between the optic nerve responsible for vision and the trigeminal nerve responsible for the sneeze reflex. When bright light stimulates the optic nerve, it may inadvertently trigger the nearby trigeminal nerve, leading to a sneeze. 2. **Genetics:** Studies indicate that the photic sneeze reflex may have a genetic component, as it seems to run in families. It's considered an autosomal dominant trait, which means that if one parent has it, there's a 50% chance it will be passed on to their children.