Herman Snellen (February 19, 1834 – January 18, 1908) was a Dutch

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

who introduced the

Snellen chart A Snellen chart is an eye chart that can be used to measure visual acuity. Snellen charts are named after the Dutch ophthalmologist Herman Snellen, who developed the chart in 1862. Many ophthalmologists and vision scientists now use an improved ...

to study

visual acuity Visual acuity (VA) commonly refers to the clarity of vision, but technically rates an examinee's ability to recognize small details with precision. Visual acuity is dependent on optical and neural factors, i.e. (1) the sharpness of the retinal ...

(1862). He took over directorship of the Netherlands Hospital for Eye Patients (Nederlandsch Gasthuis voor Ooglijders), after

Franciscus Donders Franciscus (Franz) Cornelius Donders FRS FRSE (27 May 1818 – 24 March 1889) was a Dutch ophthalmologist. During his career, he was a professor of physiology in Utrecht, and was internationally regarded as an authority on eye diseases, directi ...

Early life

Snellen studied medicine at

Utrecht University Utrecht University (UU; nl, Universiteit Utrecht, formerly ''Rijksuniversiteit Utrecht'') is a public research university in Utrecht, Netherlands. Established , it is one of the oldest universities in the Netherlands. In 2018, it had an enrollme ...

under Donders,

Gerardus Johannes Mulder Gerardus Johannes Mulder or Gerrit Jan Mulder (27 December 1802 – 18 April 1880) was a Dutch organic and analytical chemist. Life Mulder was born in Utrecht and earned a medical degree from Utrecht University. He became a reader of chemis ...

and

Jacobus Schroeder van der Kolk Jacobus Ludovicus Conradus Schroeder van der Kolk (Leeuwarden, 14 April 1797 – Utrecht, 1 May 1862) was a Dutch anatomist and physiologist and an influential researcher into the causes of epilepsy and mental illness. Schroeder van der Kolk's ...

. He earned his medical degree in 1858. He specialized in ophthalmology and worked as an assistant physician at the Netherlands Hospital for Eye Patients after he had completed his degree.

Director

He was named to succeed Donders as the institute's director in 1884, a position he served until 1903. In 1877, he was appointed as a professor of ophthalmology at

. He did research on

astigmatism Astigmatism is a type of refractive error due to rotational asymmetry in the eye's refractive power. This results in distorted or blurred vision at any distance. Other symptoms can include eyestrain, headaches, and trouble driving at nig ...

glaucoma Glaucoma is a group of eye diseases that result in damage to the optic nerve (or retina) and cause vision loss. The most common type is open-angle (wide angle, chronic simple) glaucoma, in which the drainage angle for fluid within the eye rem ...

and other

eye disease This is a partial list of human eye diseases and disorders. The World Health Organization publishes a classification of known diseases and injuries, the International Statistical Classification of Diseases and Related Health Problems, or ICD-10. ...

s as well as research on correction of visual acuity using eyeglasses and ophthalmological surgery.

Chart

While alternative versions had been developed before him, by

Eduard Jäger von Jaxtthal Eduard Model Accessories is a Czech manufacturer of plastic models and finescale model accessories. Formed in 1989 in the city of Most, Eduard began in a rented cellar as a manufacturer of photoetched brass model components. Following the su ...

and others, Snellen developed his eye chart in 1862 to measure visual acuity, which rapidly become the global standard. The most significant innovation was his use of what he called

optotype __NOTOC__ An eye chart, or optotype, is a chart used to subjectively measure visual acuity. Eye charts are often used by health care professionals, such as optometrists, physicians or nurses, to screen persons for vision impairment. Ophthalmologi ...

s, specially designed characters generated on a 5x5 grid, rather than using standard fonts. They provide a physical standard measure that could be used when printing the chart. Standard vision was measured as the ability to correctly read a line of optotype characters when they subtended 5 minutes of arc and were separated by 1 minute of arc. Since its inception, more copies of the Snellen Chart have been sold in the United States than any other poster. It remained a ubiquitous standard in medical offices into the 21st century.Bordsen, John
"Eye Chart Still The Standard For Vision"
''

The Seattle Times ''The Seattle Times'' is a daily newspaper serving Seattle, Washington, United States. It was founded in 1891 and has been owned by the Blethen family since 1896. ''The Seattle Times'' has the largest circulation of any newspaper in Washington (s ...

'', August 9, 1995. Accessed July 6, 2010.

References

External links

Biography
{{DEFAULTSORT:Snellen, Herman Dutch ophthalmologists 19th-century Dutch inventors 1834 births 1908 deaths People from Zeist Utrecht University alumni Utrecht University faculty