Photic sneeze reflex
The photic sneeze reflex (from Greek : φῶς phōs , Gen. φωτός phōtos "light") describes the phenomenon that some people have to sneeze when they are exposed to sudden brightness (e.g. sunlight).
distribution
17 to 35 percent of people have this effect in varying degrees. Women are slightly over-represented among those affected. There is a statistically significant correlation between the occurrence of the photic sneeze reflex and the presence of a curvature of the nasal septum . Most people respond by sneezing a maximum of three times within a period of 20 seconds.
causes
The causes have not been conclusively clarified. However, an autosomal dominant inheritance is very likely, which is why one speaks of the ACHOO syndrome (Autosomal Dominant Compelling Helio-Ophthalmic Outbursts of Sneezing). The most common theory assumes that in these people the optic nerve (nervus opticus) runs unusually close to the triplet nerve ( nervus trigeminus ). The latter nerve is responsible for the sensitive innervation of the face and the nasal mucosa . If a lot of action potentials are passed over the optic nerve when the brightness is suddenly high, the triple nerve is electrically stimulated, which is processed by the brain like an irritation of the nasal mucosa and is thus expressed as a sneeze stimulus . When the eye has got used to the brightness, i.e. the pupils are narrowed and the sensitivity of the retina has decreased, the urge to sneeze subsides.
The photic sneeze reflex was identified as a risk factor for military pilots, as it could possibly be distracted from the controls of their aircraft in a critical flight situation. In corresponding tests it was found that interference filters and thus also sunglasses do not offer any protection against the sneezing reflex. It is therefore assumed that it is not the wavelength but the intensity of the light that is responsible for the stimulus.
Early attempts to explain
Probably the first record of this phenomenon can be found in Pseudo-Aristotle . The author attributes sneezing not to the light but to the heat of the sun. Instead of a photic one, one would have to speak of a thermal sneeze reflex.
“Why is it easier to sneeze when you look into the sun? But probably because it sets (the sun) in motion through the warming (sneezing), as if you touch (the nose) with feathers. Because in both cases you do the same thing: by generating heat through movement, you turn the moisture into air more quickly. But the exit of this air is sneezing. "
“Why does the sneeze not happen when we are asleep, but rather entirely when we are awake? But probably because the sneeze [also] comes about through a certain warmth that sets the place in motion from which (the sneeze) originates. That is why we also turn towards the sun when we want to sneeze, while when we sleep, the heat is forced inwards. "
Almost 2000 years later, the English philosopher and statesman Francis Bacon contradicts this view. In Sylva Sylvarum or A Naturall Historie in Ten Centuries (1626), a posthumously published compilation of descriptions of nature, he takes the view that sneezing does not result from the warming of the nose. Rather, the reason is that fluid flows from the brain into the eyes and from there into the nose. However, Bacon is silent about the exact cause of this outflow of cerebral fluid. It remains to be seen whether he blames the light or the warmth. (By stating that sneezing does not result from warming the nose, Bacon does not generally rule out exposure to heat as a cause of sneezing.)
“Looking against the sun do not induce sneezing. The cause is not the heating of the nostrils, for then the holding up of the nostrils against the sun, though one wink, would do it; but the drawing down of the moisture of the brain; for it will make the eyes run with water: and the drawing of moisture to the eyes, doth draw it to the nostrils by motion of consent; and so followeth sneezing: as contrariwise, the tickling of the nostrils within, doth draw the moisture to the nostrils, and to the eyes by consent; for they also will water. But yet it has been observed, that if one be about to sneeze, the rubbing of the eyes till they run with water will prevent it. Whereof the cause is, for that the humor which was descending to the nostrils, is diverted to the eyes. "
“Looking into the sun causes sneezes. The reason for this does not lie in the warming of the nostrils - because it is already sufficient if one just holds the nostrils towards the sun for a moment - but in the drawing down of the fluid in the brain. Because it makes the eyes watery and the drawing of the liquid down to the eyes draws them in the same motion to the nostrils and so the sneezing follows. Conversely, the tickling in the nostrils draws the liquid to the nostrils and in the same way to the eyes, because these too become watery. However, it has been observed that when someone is about to sneeze, rubbing their eyes until they run in water prevents this. The reason for this is that the fluid that descends to the nostrils is diverted to the eyes. "
Mentions in fiction
The photic sneeze reflex is also repeatedly used in fiction.
Georg Büchner mentions him in the drama Woyzeck , written in 1836 :
"DOCTOR: ... I saw it, saw it with those eyes; I'm just sticking my nose out the window and letting the sunshine fall in to watch the sneeze. "
Another passage can be found in Ivan Sergeyevich Turgenev's novel Fathers and Sons , published in 1862 . In one scene of the novel, the two main characters Yevgeny and Basarov are stretched out in the hay. A medical officer arrives and says:
“ … You have chosen a wonderful spot and indulge in an excellent occupation. Lying on 'earth', looking up to 'heaven' ... You know - that has a deeper meaning!
Basarow, who feels disturbed by the medical officer’s appearance, replies:
I only look up at the sky when I want to sneeze. "
In 1868 the photic sneeze reflex found its way into Wilhelm Busch's short picture story Die Prise . A man who has taken a pinch of snuff tries different things so that the itchy nose actually leads to a relieving sneeze. A look into the sun finally brings redemption.
"And none of this helps either / A look into the sunlight helps."
There are also mentions in more recent literature:
"But at that moment I could see that he was curiously perceiving his surroundings to the left and right, that - while he was walking - he was staring at the sun with open eyes until he had to sneeze."
literature
- WR Collie, RA Pagon, JG Hall, MH Shokeir: ACHOO syndrome (autosomal dominant compelling helio-ophthalmic outburst syndrome). In: Birth Defects Orig Artic Ser. 14 (6B), 1978, pp. 361-363. PMID 728575
- EW Benbow: Practical hazards of photic sneezing. In: Br J Ophthalmol. 75 (7), Jul 1991, p. 447. PMID 1854707
- RA Breitenbach, PK Swisher, MK Kim, BS Patel: The photic sneeze reflex as a risk factor to combat pilots. In: Mil Med. 158 (12), Dec 1993, pp. 806-809. PMID 8108024
- LP Semes, JF Amos, JW Waterbor: The photic sneeze response, a descriptive report of a clinic population. In: J Am Optom Assoc. 66 (6), Jun 1995, pp. 372-377. PMID 7673597
- JM García-Moreno, MD Páramo, MC Cid, G. Navarro, MA Gamero, M. Lucas, G. Izquierdo: Autosomal dominant compelling helio-ophthalmic outburst syndrome (photic sneeze reflex), clinical study of six Spanish families. In: Neurologia. 20 (6), Jul-Aug 2005, pp. 276-282. PMID 16007510
- Why the sun tickles our noses. In: derStandard.at , March 3, 2010.
Web links
- Why does bright light cause some people to sneeze? In: Scientific American . November 18, 2002
- Why do some people have to sneeze when they look at the sun? In: Spectrum of Science . June 28, 2002.
Individual evidence
- ^ RA Breitenbach, PK Swisher, MK Kim, BS Patel: The photic sneeze reflex as a risk factor to combat pilots . In: Military medicine . tape 158 , no. December 12 , 1993, pp. 806-809 , PMID 8108024 .
- ^ A b Aristotle: Works in German translation. founded by Ernst Grumach, edited by Hellmut Flashar. Volume 19, Problemata Physica. Akademie-Verlag, Berlin 1983, p. 274 ff.
- ^ Francis Bacon: The Works of Francis Bacon, Lord Chancellor of England. A new edition by Basil Montagu, Esq. Vol. IV. William Pickering, London 1826, p. 357.
- ^ Ivan S. Turgenev: Novels. Winkler thin print edition, p. 421/422.