Jannik Petersen Bjerrum (26 December 1851 – 2 July 1920) was a Danish

ophthalmologist Ophthalmology (, ) is the branch of medicine that deals with the diagnosis, treatment, and surgery of eye diseases and disorders. An ophthalmologist is a physician who undergoes subspecialty training in medical and surgical eye care. Following a ...

who was a native of Skærbæk, a town in the southernmost part of

Jutland Jutland (; , ''Jyske Halvø'' or ''Cimbriske Halvø''; , ''Kimbrische Halbinsel'' or ''Jütische Halbinsel'') is a peninsula of Northern Europe that forms the continental portion of Denmark and part of northern Germany (Schleswig-Holstein). It ...

. In 1864 Skærbæk became part of Germany due to consequences of the

Second Schleswig War The Second Schleswig War (; or German Danish War), also sometimes known as the Dano-Prussian War or Prusso-Danish War, was the second military conflict over the Schleswig–Holstein question of the nineteenth century. The war began on 1 Februar ...

. In 1876 he received his medical doctorate from the

University of Copenhagen The University of Copenhagen (, KU) is a public university, public research university in Copenhagen, Copenhagen, Denmark. Founded in 1479, the University of Copenhagen is the second-oldest university in Scandinavia, after Uppsala University. ...

, and in 1879 became an assistant to

Edmund Hansen Grut Edmund Hansen Grut (15 January 1831 – 13 June 1907) 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 v ...

(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 (, ) is the branch of medicine that deals with the diagnosis, treatment, and surgery of eye diseases and disorders. An ophthalmologist is a physician who undergoes subspecialty training in medical and surgical eye care. Following a ...

at the University of Copenhagen, a position he would maintain until his retirement in 1910. Bjerrum made contributions regarding

pathogenetic In pathology, pathogenesis is the process by which a disease or disorder develops. It can include factors which contribute not only to the onset of the disease or disorder, but also to its progression and maintenance. The word comes . Descripti ...

research of

glaucoma Glaucoma is a group of eye diseases that can lead to damage of the optic nerve. The optic nerve transmits visual information from the eye to the brain. Glaucoma may cause vision loss if left untreated. It has been called the "silent thief of ...

, 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 The retina (; or retinas) is the innermost, photosensitivity, light-sensitive layer of tissue (biology), tissue of the eye of most vertebrates and some Mollusca, molluscs. The optics of the eye create a focus (optics), focused two-dimensional ...

. He was particularly focused on the subtleties of the central 30° of the

visual field The visual field is "that portion of space in which objects are visible at the same moment during steady fixation of the gaze in one direction"; in ophthalmology and neurology the emphasis is mostly on the structure inside the visual field and it i ...

rather than the standard

perimetry A visual field test is an eye examination that can detect dysfunction in central and peripheral vision which may be caused by various medical conditions such as glaucoma, stroke, pituitary disease, brain tumours or other neurological deficits. V ...

tests that many of his contemporaries favored. As a result of his campimetric tests he discovered a small glaucomatous

scotoma A scotoma is an area of partial alteration in the field of vision consisting of a partially diminished or entirely degenerated visual acuity that is surrounded by a field of normal – or relatively well-preserved – vision. Every normal mamm ...

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 spot to between 10° and 20° of fixation point. After Bjerrum's retirement in 1910, his work in campimetry was continued by his assistant,

Henning Rønne Henning Rønne (25 May 1878 – 28 September 1947) 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 (1851-1920) ...

(1878-1947). Jannik Petersen Bjerrum was the father of the chemist

Niels Bjerrum Niels Janniksen Bjerrum (11 March 1879 – 30 September 1958) was a Danish chemist. Niels Bjerrum was the son of ophthalmologist Jannik Petersen Bjerrum, and started to study at the University of Copenhagen in 1897. He received his Master's ...

and the brother of physicist

Kirstine Meyer Kirstine Bjerrum Meyer (12 October 1861 – 28 September 1941) was a Danish physicist and was the first woman from her country to earn a doctorate in natural sciences. Biography Kirstine Bjerrum was born in Skærbæk, Denmark and died in Helle ...

. His grandson Jannik Bjerrum (1909 – 1992), the son of Niels Bjerrum, was also a professor of chemistry at the University of Copenhagen. He was amongst the nominated candidates for the

Nobel Prize in Chemistry The Nobel Prize in Chemistry () is awarded annually by the Royal Swedish Academy of Sciences to scientists in the various fields of chemistry. It is one of the five Nobel Prizes established by the will of Alfred Nobel in 1895, awarded for outst ...

in 1965 with Gerold Karl Schwarzenbach and

Lars Gunnar Sillén Lars is a common male name in Scandinavian countries. Origin ''Lars'' means "from the city of Laurentum". Lars is derived from the Latin name Laurentius, which means "from Laurentum" or "crowned with laurel", and is therefore related to the na ...

References

Ophthalmology Hall of Fame
(biography)

Imaging and the Perimetry Society, The age of isopter perimetry: Bjerrum and the tangent screen *

External links

* {{DEFAULTSORT:Bjerrum, Jannik Petersen 1851 births 1920 deaths People from Tønder Municipality Danish ophthalmologists Academic staff of the University of Copenhagen University of Copenhagen alumni