Photic sneeze reflex, officially known as ACHOO syndrome, causes sudden sneezes when exposed to bright light. This reflex affects up to 35% of people and is linked to the crossing of optic and trigeminal nerves. While harmless, wearing sunglasses or managing allergies can reduce symptoms. Genetic and environmental factors influence its occurrence.Photic sneeze reflex, officially known as ACHOO syndrome, causes sudden sneezes when exposed to bright light. This reflex affects up to 35% of people and is linked to the crossing of optic and trigeminal nerves. While harmless, wearing sunglasses or managing allergies can reduce symptoms. Genetic and environmental factors influence its occurrence.