Larry N. Thibos (born 1947) is an American vision scientist and professor emeritus at the Indiana University School of Optometry. His research concerns the optical and neural limits to vision, including aliasing in peripheral vision, chromatic aberration of the human eye, measurement of the eye's wavefront aberrations, and the development of power vectors for describing refractive error. He chaired the Optical Society of America task force whose recommendations for reporting ocular aberrations became the basis of the ANSI Z80.28 and ISO 24157 standards.
He is a fellow of the American Academy of Optometry and of the Optical Society.
Early life and education Thibos was born in Detroit, Michigan, and grew up in Northville, Michigan. At the University of Michigan he earned a B.S. (1970) and an M.S. (1972) in electrical engineering.
At the University of California, Berkeley he worked first with Ralph Freeman on the visual effects of astigmatism; the pair reported electrophysiological evidence that abnormal early visual experience can alter the human visual system, in the condition known as meridional amblyopia. His 1975 Ph.D. thesis, supervised by Frank Werblin, examined how the vertebrate retina regulates its own sensitivity through lateral antagonism between receptive fields, and was published as two papers in The Journal of Physiology in 1978. The State University of New York later awarded him an honorary Doctor of Science (2003).
Career Australian National University From 1975 Thibos worked at the John Curtin School of Medical Research at the Australian National University in Canberra, first as a postdoctoral fellow funded by the U.S. National Institutes of Health and then as a research fellow until 1983, collaborating with William R. Levick. Their work on retinal ganglion cells, including a 1980 report of orientation bias in cat ganglion cells, argued that much complex visual processing is already determined in the retina rather than beginning in the cerebral cortex.
Indiana University Thibos joined the Indiana University School of Optometry in 1983 as assistant professor of visual science. He received tenure and promotion to associate professor in 1989 and became professor of optometry and visual science in 1994; he also held an adjunct appointment in neural science from 1987 and belonged to the cognitive science faculty from 1991. He was a founding member of the school's Borish Center for Ophthalmic Research and was named Indiana University's distinguished faculty research lecturer in 1999. His school and university service included terms as presider of the optometry faculty (1989–1992), acting director of the Institute for the Study of Human Capabilities (1991–1992), and chair of the school's tenure and promotion committee (2001–2011).
He supervised more than thirty master's and doctoral students, among them Thomas Salmon, Xin Hong, Nikole Himebaugh, Xu Cheng and Renfeng Xu, and mentored junior faculty including Donald Miller, Shaban Demirel and Pete Kollbaum. His graduate course notes on Fourier methods for vision research were later released openly as the monograph Fourier Analysis for Beginners. He retired from the faculty around 2012–13 and became professor emeritus.
Research Retinal physiology and sensory deprivation Thibos's early research covered two themes: how early visual experience shapes the brain, as in meridional amblyopia, and how the retina adjusts its sensitivity and encodes orientation and contrast.
Peripheral vision and sampling With students at Indiana, Thibos showed that patterns too fine to be resolved in the peripheral visual field can nevertheless be detected as aliases of the stimulus, evidence that peripheral acuity is limited by the coarse spacing of retinal neurons rather than by the size of their receptive fields. This began a collaboration of about forty years with Arthur Bradley, including the first systematic survey of sampling-limited resolution acuity across the visual field; later analysis suggested that mesopic acuity, and scotopic acuity beyond about 20 degrees of eccentricity, is limited by the spacing of midget ganglion cells. A 2020 review in the Annual Review of Vision Science summarizes this framework.
Chromatic aberration Thibos, Bradley and colleagues measured the eye's longitudinal and transverse chromatic aberration and its effects on image quality, and proposed the "chromatic eye", a simple reduced-eye model of ocular chromatic aberration.
Power vectors In 1997 Thibos, William Wheeler and Douglas Horner described power vectors, a Fourier-based representation of sphero-cylindrical lenses as points in a three-dimensional dioptric space, which makes lens combinations and the statistics of refractive error and astigmatism easier to analyze. The paper received the American Academy of Optometry's Garland Clay Award in 2000.
Wavefront aberrations and the Indiana Eye From the late 1990s Thibos, Bradley and Raymond Applegate studied how the eye's optical aberrations degrade the retinal image. His group was among the first to use a Shack–Hartmann aberrometer to characterize the aberrations of a large population of normal eyes, the Indiana Aberration Study, and evaluated how well subjective refraction can be predicted from wavefront aberration maps. The work led to the "Indiana Eye" optical model and, later, to models of the eye's aberrations across the visual field and during accommodation.
Standards for reporting aberrations Thibos chaired the Optical Society of America's Vision Science and its Applications (VSIA) task force on standards for reporting the optical aberrations of the eye, formed in 1999. Its recommendations, including the use of Zernike polynomials and a common notation, were published in 2000 and 2002 and became the basis of the American National Standard ANSI Z80.28 and the international standard ISO 24157.
Later work Later projects addressed wavefront-based refraction, peripheral optics, image quality with contact lenses, tear-film breakup and the eye's optics during accommodation, often with industry support from firms such as Essilor and Vistakon. In the 2020s he published historical research, including a 2023 article on Carl Bergmann and the discovery of the retinal site where vision begins.
Terminology According to his Berkeley Hall of Fame profile, terms Thibos introduced include scoton (1990), power vector (1997), aberrometer (1999) and xerop (2011), along with graphical devices such as the "Zernike tree" (2001) and the "astigmatism airplane" (2012).
Awards and honors Glenn A. Fry Award for Vision Research, American Optometric Foundation and American Academy of Optometry (1997). Garland Clay Awards of the American Academy of Optometry, for the most frequently cited paper in Optometry and Vision Science over the preceding five years: 2000 (power vectors) and 2007 (with Xu Cheng, Arthur Bradley and Xin Hong, on refractive error and aberrations). Honorary Doctor of Science, State University of New York (2003). Bruneni Lecturer in Ophthalmic Optics, Association of Schools and Colleges of Optometry (2007). J. Lloyd Hewett Award for the best original paper in Clinical and Experimental Optometry (2010). Charles F. Prentice Medal, American Academy of Optometry (2012). Inaugural Presidential Medal, College of Optometrists (2014). Induction into the Berkeley Optometry Hall of Fame, one of 21 inductees in 2023. Luminary Award for Scientific Leadership, Wavefront and Presbyopic Refractive Corrections meeting (2024).
On receiving the Prentice Medal in 2012 he became only the second Indiana University faculty member to do so, after school founder Henry Hofstetter in 1976. His Prentice lecture on the wavefront measurement of refractive state was published in Optometry and Vision Science.
Editorial and professional service Thibos served on the editorial boards of the Journal of the Optical Society of America and Optometry and Vision Science (both 1993–1999), Ophthalmic and Physiological Optics (from 2007) and the Journal of Optometry (from 2008). He was topical editor for clinical vision and visual optics at the Journal of the Optical Society of America (1993–1999), chaired the Optical Society of America's Vision Division and sat on its executive council (1996–1998), and later became an associate editor of Optometry and Vision Science (from 2011).
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Selected publications
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