Pupillary distance
As eye distance (synonyms: interpupillary distance ( IPD ), Pupillardistanz ( PD ), pupil distance ) is known in the ophthalmology and optometry each of both eyes the distance specified in millimeters. It must be taken into account when fitting glasses and is used to align the optical axes of spectacle lenses ( main visual point ) with those of the eyes ( eye axes ).
physiology
The eye relief for humans is on average 65 mm (men) or 62 mm (women), but can vary between approx. 52 mm and 78 mm depending on the constitution and size.
According to scientific research, the interpupillary distance can, if only to a small extent, influence the ability to distinguish between distances.
The eye relief is used as a biometric feature in face recognition .
Using your own thumb and the interpupillary distance, the distance to an object can be estimated using the theorem of rays when jumping the thumb .
pathology
| Classification according to ICD-10 | |
|---|---|
| Q75.2 | Hypertelorism |
| ICD-10 online (WHO version 2019) | |
Too large or too small a distance between the eyes can be due to illness.
Hypertelorism
The term hypertelorism describes a comparatively large eye relief. Often hypertelorism is accompanied by telekanthus . Hypertelorism is defined as a distance between the centers of the pupils (interpupillary distance, IPD) above the 97% percentile as a proportion of a distribution in the normal population. In adult women, an interpupillary distance greater than 65 mm, in men greater than 70 mm, is called hypertelorism.
Hypertelorism is not necessarily a symptom of a disease. Quite often it is an isolated anomaly that is often perceived as an attractive feature by women to some extent. Famous examples are Liza Minnelli and Jacqueline Kennedy Onassis . Pronounced or asynchronous hypertelorism can be a serious cosmetic defect and speak for a surgical correction of the distance between the eye sockets.
Hypertelorism is part of a large number of syndromes , for example it is found in people with the cat- cry syndrome (5p, Cri-du-chat syndrome), Wolf-Hirschhorn syndrome (4p-), Zellweger syndrome , triploidy , Noonan syndrome , Gorlin-Goltz syndrome , Fraser syndrome , trisomy 14 , Edwards syndrome (trisomy 18), trisomy 22 , LEOPARD syndrome , De Grouchy syndrome , Mabry syndrome , Crouzon's disease and Dubowitz syndrome , Down syndrome ( Trisomy 21), Alagille syndrome , Naguib-Richieri-Costa syndrome . With hypertelorism of the Teebi type or ATR-X syndrome .
Hypotelorism
The term hypotelorism describes a comparatively small eye relief. It is common in people with Patau syndrome (trisomy 13), trisomy 8 , trisomy 9 , holoprosencephaly, or fetal alcohol syndrome .
Measurement
The reference point for measuring the interpupillary distance is either the center of the pupil or the outer edge of the iris . Because of the dynamic pupil play, the latter is easier to assess, especially for inexperienced examiners. The determination is made either by adding up the right and left eye distances from the center of the pupil to the center of the root of the nose or by measuring the distance between the right and left edges of the iris. As a rule, the values for the distance between the right and left center of the pupil and the center of the face are recorded individually in a glasses passport (e.g. 32 mm / 33 mm), which enables asymmetries to be documented and, in this respect, greater precision for determining the visual points in the lens allows as a measurement from eye to eye (e.g. 65 mm).
In addition to the manual measurement with a ruler, an even more precise measurement can be carried out with a video centering system .
Your own interpupillary distance can be measured with a certain degree of accuracy if you aim at a distant point first with one eye and then with the other eye using a ruler held at a short distance and determine the difference between the values read.
Optical devices and corrective glasses
There are special devices for setting the eyepiece distances of optical devices that have a binocular tube , which take into account the individual eye distance and thus ensure an optimal perspective.
When producing corrective glasses, the eye relief is used to correctly center the lenses. This distance can therefore be documented in a glasses pass .
Another meaning of the term “interpupillary distance” is the distance from eye to eyepiece, which should not exceed a certain value in order not to restrict the field of view.
Web links
literature
- Albert J. Augustin: Ophthalmology. Springer Verlag, Berlin 2007, ISBN 978-3-540-30454-8 .
Individual evidence
- ^ Neil A. Dodgson: Variation and extrema of human interpupillary distance. In: Stereoscopic Displays and Virtual Reality Systems XI. January 19-22, 2004, San Jose, California, USA. Proceedings of Electronic Imaging, Science and Technology. (= SPIE, International Society for Optical Engineering. Proceedings. 5291). SPIE, Bellingham WA 2004, ISBN 0-8194-5194-0 , pp. 36-46 (PDF file; 235 kB).
- ^ Roland Gockeln: The influence of the interpupillary distance on the depth of vision. In: Clinical monthly sheets for ophthalmology. Vol. 209, No. 10, 1996, ISSN 0023-2165 , pp. 205-210, doi : 10.1055 / s-2008-1035303 .
- ↑ Lech Korniszewski: Dziecko for zespołem wad wrodzonych: Diagnostyka dysmorfologiczna. PZWL, 1994, ISBN 83-200-1808-0 .
- ↑ Joachim E. Zöller, Alexander C. Kübler, Wilma D. Lorber, Joachim Mühling: Craniofacial surgery . Thieme Verlag, Stuttgart 2003, ISBN 3-13-131391-9 .
- ^ A b Wolfgang Hammerstein, Walter Lisch: Ophthalmologische Genetik . Enke Verlag, Stuttgart 1985, ISBN 3-432-94941-3 .
- ↑ Modern video centering systems and pupillometers in comparison, Part 1 , Wolfgang Wesemann, DOZ 6-2009 ( Memento of the original from September 24, 2015 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Patent device for adjusting the pupil distance in eyepieces , publication number DE102005043646 A1 from October 2006
