Jannik Peterson Bjerrum
Encyclopedia
Jannik Petersen Bjerrum was a Danish ophthalmologist who was a native of Skærbæk
, a town in the southernmost part of Jutland
. In 1864 Skærbæk became part of Germany due to consequences of the Second Schleswig War.
In 1876 he received his medical doctorate from the University of Copenhagen
, and in 1879 became an assistant to Edmund Hansen Grut
(1831-1907) at the Havnegade eye clinic. After Grut's retirement in 1896, he became director of the clinic, as well as being the second professor of ophthalmology
at the University of Copenhagen, a position he would maintain until his retirement in 1910.
Bjerrum made contributions regarding pathogenetic
research of glaucoma
, and performed extensive investigations involving campimetry
. He was interested in the correlation between visual perception of form and the resolving power in localized regions of the retina
. He was particularly focused on the subtleties of the central 30° of the visual field
rather than the standard perimetry
tests that many of his contemporaries favored.
As a result of his campimetric tests he discovered a small glaucomatous scotoma
that was to become known as a "Bjerrum scotoma", which is a visual field defect that goes by several other names, such as "sickle scotoma", "arcuate scotoma" or "scimitar scotoma". Other eponyms named after Bjerrum include:
After Bjerrum's retirement in 1910, his work in campimetry was continued by his assistant, Henning Rønne
(1878-1947).
Jannik Petersen Bjerrum was the father of the chemist Niels Bjerrum
and the brother of physicist Kirstine Meyer
.
Skærbæk
Skærbæk is a town with a population of 3,117 and a former municipality on the coast of Tønder municipality in Region of Southern Denmark on the Jutland peninsula in south Denmark...
, a town in the southernmost part of Jutland
Jutland
Jutland , historically also called Cimbria, is the name of the peninsula that juts out in Northern Europe toward the rest of Scandinavia, forming the mainland part of Denmark. It has the North Sea to its west, Kattegat and Skagerrak to its north, the Baltic Sea to its east, and the Danish–German...
. In 1864 Skærbæk became part of Germany due to consequences of the Second Schleswig War.
In 1876 he received his medical doctorate from the University of Copenhagen
University of Copenhagen
The University of Copenhagen is the oldest and largest university and research institution in Denmark. Founded in 1479, it has more than 37,000 students, the majority of whom are female , and more than 7,000 employees. The university has several campuses located in and around Copenhagen, with the...
, and in 1879 became an assistant to Edmund Hansen Grut
Edmund Hansen Grut
Edmund Hansen Grut was a Danish ophthalmologist born in Copenhagen.In 1857 he earned his medical doctorate at the University of Copenhagen, and afterwards traveled to Berlin, where he studied with Albrecht von Graefe...
(1831-1907) at the Havnegade eye clinic. After Grut's retirement in 1896, he became director of the clinic, as well as being the second professor of ophthalmology
Ophthalmology
Ophthalmology is the branch of medicine that deals with the anatomy, physiology and diseases of the eye. An ophthalmologist is a specialist in medical and surgical eye problems...
at the University of Copenhagen, a position he would maintain until his retirement in 1910.
Bjerrum made contributions regarding pathogenetic
Pathogenesis
The pathogenesis of a disease is the mechanism by which the disease is caused. The term can also be used to describe the origin and development of the disease and whether it is acute, chronic or recurrent...
research of glaucoma
Glaucoma
Glaucoma is an eye disorder in which the optic nerve suffers damage, permanently damaging vision in the affected eye and progressing to complete blindness if untreated. It is often, but not always, associated with increased pressure of the fluid in the eye...
, and performed extensive investigations involving campimetry
Perimetry
Perimetry or campimetry is the systematic measurement of differential light sensitivity in the visual field by the detection of the presence of test targets on a defined background. Visual field testing can be performed clinically with confrontational field testing keeping the subject's gaze fixed...
. He was interested in the correlation between visual perception of form and the resolving power in localized regions of the retina
Retina
The vertebrate retina is a light-sensitive tissue lining the inner surface of the eye. The optics of the eye create an image of the visual world on the retina, which serves much the same function as the film in a camera. Light striking the retina initiates a cascade of chemical and electrical...
. He was particularly focused on the subtleties of the central 30° of the visual field
Visual field
The term visual field is sometimes used as a synonym to field of view, though they do not designate the same thing. The visual field is the "spatial array of visual sensations available to observation in introspectionist psychological experiments", while 'field of view' "refers to the physical...
rather than the standard perimetry
Perimetry
Perimetry or campimetry is the systematic measurement of differential light sensitivity in the visual field by the detection of the presence of test targets on a defined background. Visual field testing can be performed clinically with confrontational field testing keeping the subject's gaze fixed...
tests that many of his contemporaries favored.
As a result of his campimetric tests he discovered a small glaucomatous scotoma
Scotoma
A scotoma is an area of partial alteration in one's field of vision consisting of a partially diminished or entirely degenerated visual acuity which is surrounded by a field of normal - or relatively well-preserved - vision.Every normal mammalian eye has a scotoma in its field of vision, usually...
that was to become known as a "Bjerrum scotoma", which is a visual field defect that goes by several other names, such as "sickle scotoma", "arcuate scotoma" or "scimitar scotoma". Other eponyms named after Bjerrum include:
- Bjerrum tangent screen: Screen used to assess the central 30° of the visual field.
- Bjerrum's area: An arcuate region that extends above and below the blind spotBlind spot (vision)A blind spot, also known as a scotoma, is an obscuration of the visual field. A particular blind spot known as the blindspot, or physiological blind spot, or punctum caecum in medical literature, is the place in the visual field that corresponds to the lack of light-detecting photoreceptor cells on...
to between 10° and 20° of fixation pointFixation (visual)Fixation or visual fixation is the maintaining of the visual gaze on a single location. Humans typically alternate saccades and visual fixations, the notable exception being in smooth pursuit, controlled by a different neural substrate that appear to have developed for hunting prey...
.
After Bjerrum's retirement in 1910, his work in campimetry was continued by his assistant, Henning Rønne
Henning Rønne
Henning Rønne was a Danish ophthalmologist. He studied medicine at the University of Copenhagen, where he graduated with an M.B. in 1903. Later he became an assistant to Jannik Petersen Bjerrum , with whom he performed important studies in campimetry...
(1878-1947).
Jannik Petersen Bjerrum was the father of the chemist Niels Bjerrum
Niels Bjerrum
Niels Janniksen Bjerrum, born March 11, 1879 in Copenhagen, died September 30, 1958, was a Danish chemist.Niels Bjerrum was the son of opthamologist Jannik Petersen Bjerrum, and started to study at University of Copenhagen in 1897. He received his Master's degree in 1902 and his Doctor's degree in...
and the brother of physicist Kirstine Meyer
Kirstine Meyer
Kirstine Bjerrum Meyer was a Danish physicist. She was a high school teacher for many years, working on her education and research in physics at the same time...
.