Tom Cornsweet

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Tom N. Cornsweet
Born(1929-04-29)April 29, 1929
DiedNovember 11, 2017(2017-11-11) (aged 88)
Alma materCornell University, Brown University
Known forCornsweet illusion
Scientific career
FieldsOphthalmology, psychology
InstitutionsYale University (1955–1959), University of California, Berkeley, Stanford Research Institute, Stanford University, Baylor College of Medicine, University of California, Irvine, Brien Holden Vision Diagnostics

Tom Norman Cornsweet[1] (April 29, 1929 – November 11, 2017) was an American experimental psychologist known for his pioneering work in visual perception, especially the effect that bears his name, and in the development of ophthalmic instrumentation.[2][3]

Academic background and scientific research[edit]

Cornsweet is known for documenting the effect that bears his name in the 1960s.[4] Prior to his work on this particular optical illusion, Cornsweet graduated from Cornell University and enrolled in a graduate program at Brown University, operating in the vision research laboratory of Lorrin A. Riggs.[5][6] During his graduate studies he was co-author of an early paper describing stabilized images.[5] His 1955 Ph.D. dissertation in experimental psychology involved small movements of the eye. Cornsweet was an assistant professor at Yale University from 1955–1959, and then became professor of psychology at the University of California, Berkeley. His interest in psychophysics led him to develop a widely employed improvement in the staircase method.[7] As an outgrowth of the courses he taught, Cornsweet published a frequently-cited textbook.[8]

Inventor and entrepreneur[edit]

In the late 1960s and early 1970s, Cornsweet was a key member of the Bioinformation Systems Group at the Stanford Research Institute (SRI). While also teaching in the psychology department at Stanford University, he designed or co-designed several innovative instruments for measuring properties of the eye, including eyetrackers,[9] auto-refractors,[10] and optical fundus scanners.[11] He left SRI to become Chief Scientist at Acuity Systems of Reston Virginia, where he developed the first commercial auto-refractor in 1973. It gave the objective reading of the refractive index of the eye in one second, saving practitioners up to 15 minutes a patient. This saved the Ophthalmologist more than an hour a day on average, immediately adding a huge productivity and income boost. Acuity Systems introduced the worlds first Auto-refractor and sold approximately 3000 world wide between 1975 and 1979 before it was bought by Simmons Instruments Inc. Many copies followed made by Coherent Radiation of California, Nidek of Japan and others. All versions of the Auto-refractor sold are estimated to total $15bn as the instrument is now universally commonplace in the Optometrist and Ophthalmologist workplaces. The Auto-refractor saved sight in many cases. One of many such instances occurred in Sydney Australia when a severely myopic patient, blind because the closest his expert optometrist could come to prescribing spectacles was 5.75 diopter sphere, 3.75 diopter cylinder at an incorrect angle, and the Auto-refractor immediately six times indicated a prescription of 15.75D sphere x 5.75D cylinder at 108 degrees. The patient was seen leaving the practise and heard proclaiming “I can see, I can see!” Multiple thousands of such instances occurred worldwide. A device to measure the refractive index of spectacle lenses, the Auto-lensmeter was also a commercial success in parallel with the Auto-refractor. In the 1980’s Tom Cornsweet developed a number of devices including one which measured the density of cataracts, ESA, the Eye System Analyser, which in a 30 second eye test determined presence of diseases of the nervous or muscular system such as MS 15 years before its noticeable onset, Hopkinson disease two years before onset and many other diseases. An industrial version, FIT 2000, first installations worldwide implemented in the coal mines of Queensland Australia, and later in mines of Chile, resulted in huge safety gains in the workplace, detecting immediately up to 5% of the workforce were participating in sleep deprivation activity, drug taking, prescription medication overuse and alcohol abuse. After a 36 second daily eye test and a ten day baseline was established, it was very easy to determine the presence of drugs, which drugs, alcohol, lack of sleep, and, after medical referral, diseases such as Narcolepsy, Brain diseases and damage. The FIT2000, sold and manufactured by PMI of Rockville, Maryland has also been installed worldwide into Armed forces for such things as fatigue detection in pilots and soldiers required to undertake military activities with severe sleep deprivation over many days. Cornsweet continued to invent devices for measuring various properties of the eye and also to teach, first at the Baylor College of Medicine and later at the University of California, Irvine.[12] He served as Vice President of research and development for Sensory Technologies from 1994 to 1997. In 1999 Cornsweet retired from UC–Irvine and co-founded Visual Pathways, where his team developed an automated retinal imaging system intended for the diagnoses of glaucoma, cataracts, diabetic retinopathy and macular degeneration. Visual Pathways folded into the Brien Holden Vision Institute after several years and successfully installing 24 breakthrough 3D fundus cameras, where from 2013 to 2015, Tom Cornsweet was Chief Scientist at Brien Holden Vision Diagnostics (formerly Quantum Catch),[13] a company developing very low-cost ophthalmic 3D fundus cameras and instruments for detection and monitoring of eye, brain and muscle disease primarily and principally for 3rd world countries which could not afford available instrumentation. Until his death in 2017, Cornsweet was Professor of Cognitive Science, Electrical and Computer Engineering, and Ophthalmology, Emeritus, University of California, Irvine.[14]

Patents and awards[edit]

  • 40 patents, primarily in the area of optical and ophthalmic instrumentation
  • UC Berkeley Distinguished Teaching award 1961[15]
  • Charles F. Prentice Medal Award[16] from the American Academy of Optometry, 1984


Cornsweet wrote three books and published more than 100 journal articles.[17]

  • The Design of Electric Circuits in the Behavioral Sciences. John Wiley & Sons. 1963.
  • Visual Perception. Academic Press. 1970.
  • Why is Everything!: Doing Science[18]

Seeing.How light tells us about the world.Tom Cornsweet.2017.Publisher University of California presS.

Journal articles

List of publications adapted from Cornsweet's curriculum vitae, published by the University of California, Berkeley.[19]


  1. ^ Osborne, Roy (2016-12-29). Books on Colour 1495-2015: History and Bibliography. ISBN 9781326459710.
  2. ^ Purves, Dale (January 8, 2010). Brains: How They Seem to Work. FT Press. pp. 139–142. ISBN 9780137060283. Retrieved December 23, 2013.
  3. ^ American Men of Science: Physical and Biological Sciences. Providence, N.J.: Bowker RR. 1967.
  4. ^ Plait, Phil (December 7, 2013). "Viral Illusion Will—and Should—Have You Doubting Your Eyes". Slate. Retrieved December 23, 2013.
  5. ^ a b Riggs, Lorrin A.; Ratliff F.; Cornsweet J.; Cornsweet T. (1953). "The Disappearance of Steadily Fixated Visual Test Objects". Journal of the Optical Society of America. 43 (6): 495–500. Bibcode:1953JOSA...43..495R. doi:10.1364/josa.43.000495. PMID 13070111. Retrieved March 20, 2011.
  6. ^ D.H. Kelly, ed. (March 30, 1994). Visual Science and Engineering: Models and Applications. CRC Press. p. 91. ISBN 9780824791858. Retrieved December 23, 2013.
  7. ^ Cornsweet, TN (September 1962). "The Staircase-method in Psychophysics". Am. J. Psychiatry. 75 (3): 485–491. doi:10.2307/1419876. JSTOR 1419876.
  8. ^ Cornsweet, Tom N. (1970). Visual Perception. New York, NY: Academic Press. p. 475. ISBN 978-0-12-189750-5.
  9. ^ Cornsweet, TN; Crane HD (1973). "Accurate two-dimensional eye tracker using first and fourth Purkinje images". Journal of the Optical Society of America. 63 (8): 921–928. Bibcode:1973JOSA...63..921C. doi:10.1364/JOSA.63.000921. PMID 4722578. Retrieved March 20, 2011.
  10. ^ Cornsweet, TN (August 1973). "Computer-assisted automated refractions". The Australian Journal of Optometry. 56 (8): 310–313. doi:10.1111/j.1444-0938.1973.tb00727.x.
  11. ^ Kelly, DH; Crane; Hill; Cornsweet (1969). "Non-contact method of measuring small eye- movements and stabilizing the retinal image". J. Opt. Soc. Am. 59: 509.
  12. ^ "Conferences, Workshops, Seminars" (PDF). The Linguistic Reporter. Center for Applied Linguistics. December 1982 – January 1983. p. 9. Retrieved December 23, 2013. Note: Part of The Linguistic Reporter (1959–1982), Volume 25, published in 1982.
  13. ^ "Leap in Detection and Diagnoses of Eye and Other Disorders". Medical Design Technology. Advantage Business Media. August 3, 2012. Retrieved December 23, 2013.
  14. ^ "Obituary: Tom N. Cornsweet". Retrieved 23 November 2017.
  15. ^ "UC Berkeley teaching award".
  16. ^ "Charles F. Prentice award". Retrieved March 21, 2011.
  17. ^ "TN Cornsweet Google Scholar publications". Retrieved March 21, 2011.
  18. ^ Cornsweet, Tom. "Why is Everything!: Doing Science by Tom Cornsweet". Retrieved December 17, 2013.
  19. ^ "Curriculum Vitae: Tom N. Cornsweet: Professor of Cognitive Science, Electrical and Computer Engineering, and Ophthalmology, Emeritus: University of California, Irvine" (PDF). University of California, Berkeley. Retrieved December 17, 2013.

External links[edit]