The photic sneeze reflex also known as ACHOO is a condition that causes variable difficulty to control sneezing in response to numerous stimuli, such as looking at bright lights or periocular injection.
The condition affects 18-35% of the population in the United States, but its exact mechanism of action is not well understood.
The photic sneeze reflex manifests itself in the form of uncontrollable sneezing in response to a stimulus which would not produce a sneeze in people without the trait. The sneezes generally occur in bursts of 1 to 10 sneezes, followed by a refractory period that can be as long as 24 hours.
A photic sneeze is the most common manifestation of the photic sneeze reflex. A photic sneeze results from exposure to a bright light. The photic sneeze reflex seems to be caused by a change in light intensity rather than due to a specific wavelength of light.
Photic sneezes are harmless annoyances for the most part, but can pose physical risk to people who are operating vehicles or machinery that involve precise movement and reactions.
A study conducted by the School of Optometry at the University of Alabama at Birmingham, found that females represent 67% of photic sneezers, and Caucasians represent 94%.
The study also found statistically significant correlations between photic sneezing and the presence of a deviated nasal septum. The study also showed that photic sneezing is more likely to be acquired than inherited.
During surgeries in and around the eye, such as corneal transplant surgery, the patient often requires injection of a local anesthetic into the eye.
In patients who show the photic sneeze reflex, an injection into the eye, such as that undergone in a retrobulbar or peribulbar block, can often elicit a sneeze from the patient. During these procedures, the patient may be sedated prior to the periocular injection.
The patient begins to sneeze just as the needle is inserted into the eye, often resulting in the anesthesiologist having to remove the needle before injecting the local anesthetic in order to avoid damaging the patient’s eye.