About

Gerald Westheimer is a Professor of the Graduate School in the Department of Neuroscience at UC Berkeley. His research interests focus on perceptual learning in spatial visual tasks. As a faculty member, he contributes to the understanding of how visual perception adapts and improves through experience, particularly in tasks involving spatial vision. His role involves mentoring graduate students and advancing research in neuroscience related to perceptual processes.

Research topics

• Optics
• Computer science
• Psychology
• Optometry
• Artificial intelligence

Selected publications

• History of physiological optics in the 20th century

  2026-04-30

  book-chapter1st authorCorresponding
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• Defocus degradation of retinal images in the Maxwellian view

  Journal of the Optical Society of America A · 2025-04-02 · 2 citations

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  In the Maxwellian view, the defocused retinal image is derived from two superimposed pupil wavefront components: the diffraction pattern that results when the source transilluminating a target is imaged in the eye's entrance pupil and the wavefront deviation associated with defocus. Since the diffraction pattern based on the target configuration will differ from case to case, there is no general theory of defocus degradation such as the optical transfer function in conventional retinal imagery. Nevertheless, depth of focus is always better in the Maxwellian view because the excitation in the wavefront does not fill the pupil fully and uniformly. The robustness to defocus image degradation is illustrated in several examples.

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• Jay M. Enoch (1929–2025), Berkeley Optometry Dean and leading retina researcher: A biographical memoir of an important 20th‐century vision researcher and optometric educator, by one of his contemporaries

  Optometry and Vision Science · 2025-07-22

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  When Jay Enoch became Dean of the School of Optometry of the University of California at Berkeley in 1980, it was a homecoming of sorts. He had graduated from the optometry program of Columbia University in 1950, served as an optometrist in the US Army and then did graduate study with the legendary Dr. Fry at the School of Optometry at The Ohio State University, receiving the PhD in 1956. But when the social climate denied him the kind of teaching and research faculty position in a university optometry program that he merited, he embraced the warm welcome he was accorded in medical school ophthalmology departments. At the time, Dr. Bernard Becker at Washington University, St. Louis, was arguably the most prominent leader in American academic ophthalmological circles, and in 1958, he gave Enoch the opportunity to unfold his talent for pure and, as we would now call it, translational research, and also for fostering wider social, organizational, and political advances of the eye care community. During his 10 years on a National Institutes of Health Career Development Award, he pursued the research in retinal structure and function started in his PhD project, utilized contact lenses to enable normal visual development in aniridic and aphakic infants, and pioneered psychophysical probing for diagnosis of retinal diseases. Enoch did yeoman service in two areas that had wider and lasting impact: establishing the National Eye Institute and the Association for Research in Vision and Ophthalmology (ARVO). The National Eye Institute’s emergence as a separate entity in the National Institutes of Health, one devoted entirely to the eye instead of being just part of the larger portfolio of the National Institutes of Neurological Diseases and Blindness, was set into motion by a two-volume report, edited by Jay Enoch, that was the basis for its congressional mandate. ARVO, now the premier showcase and publication platform for eye research, arose in the 1960’s when the need for a more encompassing professional organization became clear and, largely through Enoch’s efforts, ophthalmological circles agreed to include the word “Vision” in the title and the mission of their hitherto more modest and limited Association for Research in Ophthalmology. All along, during this time, Jay kept in touch with the wider vision research community by building on personal contacts made as a graduate student and by avid participation in professional organizations and congresses (Fig. 1).Fig. 1.: Jay Enoch (right) demonstrating to Con Kraft, a leading engineering psychologist and fellow Ohio State graduate student, new optical equipment invented by Tom Cornsweet (left) at SRI, Palo Alto, mid-1960s.When Dr. Becker retired, much of his leadership role in ophthalmology devolved on Dr. Herbert Kaufman, and when Kaufman moved to the University of Florida in Gainesville in 1974, Enoch moved with him and continued his fundamental and translational research there. Eventually, however, the time was ripe for both Jay Enoch and the optometric profession, and he was offered and accepted the leadership position in the most prominent academic institution housing an optometry school. That had major consequences, not so much for Enoch’s own research or even for vision research at Berkeley, as for the existence of the school itself on the Berkeley campus. The gradual evolution of the profession from the prewar “optometrist and optician” with practice centered on testing for and providing refractive aids, to the 21st century “optometric physician” with full drug and some therapeutic privileges and even knocking at the door of laser surgery, had gone about halfway by the time Enoch arrived in Berkeley. Pivoting from 2 to 4 years programs, from bachelor’s to officially conferred doctorate degree, from teaching lens grinding to pharmacology, was relatively uncomplicated in private optometry colleges, but encountered major opposition at each step where optometry was a unit in large universities, and more so the more prominent and medically influenced the institution. Columbia University’s optometry program collapsed under the pressure in 1954; as an optometry faculty member I personally witnessed the immense effort needed to have The Ohio State University and the University of California accede to the optometric profession’s edict of converting their degree to the OD, “or else.” Enoch’s challenge on arriving in Berkeley was at the next level. Problems of running an optometry school with separate needs for preclinical and clinical faculty, and operating a health-care clinic, were more akin to those of medical schools than the typical Berkeley colleges, even the professional ones like law and public health. When Enoch clearly articulated the financial and organizational requirements to update the school, based on his experience in clinical departments of medical schools, the university administration, quite reasonably from their standpoint, suggested that the school move from Berkeley to the San Francisco Medical Campus. Assessing the peril that this might pose for the independence of the optometric professional program, Enoch spent almost all of the rest of his tenure as Dean to ensure that this did not happen and to make the administrative and financial arrangements, still ongoing to this day, to create adequate physical facilities for the school’s clinical and research units. In this, he had the advantage of being personally acquainted with and accepted in professional and academic ophthalmological circles. During all of his time in California, he also had a professorial appointment in ophthalmology at the University of California, San Francisco, Medical School. There is, however, a fundamental difference between the prerogatives of a clinical department chairman in a medical school and the more collegial demands on a Berkeley academic administrator. Enoch managed to bridge the difference and use campus resources to build an active research unit that extended beyond the completion of his term as Dean (when he was succeeded by Tony Adams). Having already been honored by the presidency of ARVO and its Proctor Medal, the American Academy of Optometry’s Prentice Medal, and the PISAR award, he enjoyed a Festschrift meeting with wide national and international attendance in 1993. He retired in 1994, receiving the Berkeley Citation, the campus’s highest accolade. Jay derived particular pleasure from the two honorary degrees he was awarded, often gleefully identifying himself, in the European fashion, as “Drs. Sci.h.c.mult.” EARLY RESEARCH 1948–1958 It should not surprise that Jay started in eye research already as an optometry student at Columbia University in the late 1940s. He had two outstanding mentors, for whose influence he was grateful for the rest of his life and whose integrity and dedication he tried to emulate. George Smelser, professor of anatomy at Columbia University Physicians & Surgeons, and Isadore Finkelstein, Columbia Optometry faculty, were engaged in the study of the effect of the then primitive scleral contact lenses on the cornea and Jay was a research intern in their labs, quickly becoming, at age 20, a valued member of their teams and remaining close to both till their early deaths. When Jay became a commissioned optometry officer in the US Army after graduation, he naturally gravitated to the Army’s contact lens investigation facilities and was an author of some official reports and publications in this area.1 He continued to utilize his contact lens expertise while associated with ophthalmology clinics and achieved recognition for fitting neonates after the removal of congenital cataract. On his discharge from the army, having decided on an academic and research career, Jay enrolled as a graduate student in the University of Rochester. There he got to know Robert Boynton who had just arrived in the psychology department after a PhD in electroretinography with Lorrin Riggs. They became life-long friends and Jay was coauthor of a couple of papers in which the stray light distribution of bovine eyes was estimated.2 Although the director, Brian O’Brien, had a presence in vision research, the general theoretical, highly mathematical, approach of the Rochester optics program was not a good fit and Jay took the significant step of transferring his graduate studies to The Ohio State University Optometry School, led for 25 years by Glenn Fry. For his dissertation project, he went along with Fry’s interest in the Stiles-Crawford effect, whose proximal cause was conjectured to be optical channeling in the retinal cones. Enoch had seen a curious attempt at Rochester to approach this by means of measurements on scaled-up models of retinal cones. Fry and Enoch’s decision to follow this up required an enormous effort involving construction of Styrofoam cones, a large aluminum reflecting surface, the generation and measurement of microwave radiation. Funded in part by the US Air Force, and utilizing the extensive workshop facilities that Fry included in his design of Ohio State’s new two-story optometry building, the project played to the strengths and attributes of the two: Jay Enoch had great mechanical aptitude, virtual unlimited energy and an unrivaled capacity to put a positive spin on any situation; Glenn Fry, had a remarkable geometrical intuition and always managed to transform a scientific question into one involving the construction of elaborate apparatus. The project went on for years and resulted in a high-caliber publication in the Journal of the Optical Society of America.3 As was often the case for PhD work under Fry, the elaborate apparatus (Fig. 2), which he enjoyed designing, was not fully operative by the time the dissertation was due, and the candidate had to scramble to obtain data with more modest existing set-ups. In Jay’s case, this took the form of a very respectable demonstration of the nonadditivity of pupil zones in generating brightness. The Stiles-Crawford effect remained a prominent item in Jay’s research portfolio. It motivated him to spend a year in London with Stiles himself, where they measured and theorized about pupil position-varying color phenomena.4 But the microwave model research with Fry made Enoch a prime proponent of the waveguide theory of the origin of the directional sensitivity of cones and spearhead several compendia devoted to comparative aspects of photoreceptors. In wider scientific circles, this is what Jay is best known for.Fig. 2.: Jay Enoch and Glenn Fry fine-tuning their apparatus to measure the Stiles-Crawford effect in a scaled-up microwave model on the front lawn of The Ohio State University Optometry Building, 1956.RETINAL STRUCTURE AND FUNCTION With generous resources, academic support and full access to clinical facilities, Jay’s voluminous research output during the 1960’s and 1970’s reported on his effort to probe the structural and functional deficits underlying retinal dysfunction. In the days before OCT, he used Fechnerian psychophysics on patients with defined diseases to pinpoint the pathology’s locus in the flow of signals through the retina,5 a procedure he termed “layer-by-layer perimetry.” Well-funded laboratories, strong administrative support, a research appointment in settings that fostered translational research, training and experience in both the laboratory and the clinic, all these enabled Jay to advance research in the three principal foci of his scientific curiosity: contact lenses,6 photoreceptor optics,7 and the pathophysiology of the retina. Jay took advantage of the platform to entrain some prominent international collaborations. Hans Goldmann from Bern, Switzerland, one of the most important figures in 20th-century ophthalmology, became his strong supporter and dear friend. So did Emilio Campus in Bologna, Italy, and later Maria Calvo, Madrid, Spain. With more leisure after retirement, Jay took up occasional topics that piqued his interest: whether glass baubles in museums, thousands of years old, had been intended to be lenses or just ornaments. These were always meticulously researched in their original locations, usually with the willing help of the collections’ curators and other experts.8 His identification with professional optometry, dormant during the St. Louis and Gainesville days, took new forms: being instrumental in founding a major optometry school in India, and contributing biographies and perspective essays to “Hindsight,” journal of optometric history. PERSONAL LIFE Jay Martin Enoch was born on April 20, 1929, as the only child in a middle-class household in the Bronx. The time and place—the midst of the Great Depression, in that particular borough of New York City with its pre-WWII ethnic mix—is likely to have helped shape his personality and career plans. At any rate, as a bright, active boy he gained enrollment in the Bronx High School of Science, a breeding ground of a generation of intellectual leaders, and from there, on a Regent’s Scholarship at age 17 in 1946, in Columbia University. This is where Selig Hecht had just announced the quantum basis of the visual threshold, and where I. I. Rabi presided over one of the leading physics departments. The critical juncture of Jay’s life was the decision after his sophomore year, said to be at the family’s urging, to switch to Columbia’s two-year optometry curriculum, graduation from which would open a secure future in a respected line of work. Being an optimistic, forward-looking individual, he had barely begun his optometry studies, before he veered in the direction, not of financial gain or even professional practice, but of intellectual adventure, scientific interest, interpersonal interaction within a group, that was promised by participation in Smelser’s and Finkelstein’s laboratories. These traits defined him for the next 70 years. He married Rebekah Feiss while still in the army. The source of much his success, and certainly of his ability to concentrate so singularly on the imperatives of a varied career, was Becky’s even-tempered, level headed management of the household and sustenance of a stable home environment in the face of moving from Ft. Knox, Kentucky, to Rochester, New York, to Columbus, Ohio, to St. Louis, Missouri, to Gainesville, Florida, to Berkeley, California, finally to retirement in Kirkland, Washington. During their 72-year marriage, Becky, with quiet competence, took care of the many ancillary routines that come with scientific and academic leadership. On his death on March 16, 2025, in addition to Becky, Jay was survived by their three children, Harold, Barbara, and Ann, five grandchildren and two great-grandchildren. Among the several colleagues who became close friends—Bob Boynton, Herschel Leibowitz, Bob Moses, the author (Fig. 3), —among his graduate students—Harold Bedell, Stacey Choi, and Vengu Lakshminarayanan, who all became optometric educators—among the mentors and department heads under whom he served—Finkelstein, Becker, Kaufman,—and among his many junior collaborators, he was universally held in high esteem for his loyalty, support, good cheer and positive attitude. These traits earned him deep admiration even if it was not always easy to follow his example.Fig. 3.: Jay Enoch, acting as Dean of the School of Optometry, greeting the author on some festive occasion in Berkeley, 1989.ACKNOWLEDGMENTS Photos generously provided by the Archives of the School of Optometry, University of California (Figs. 1, 3–5), and Archives of the College of Optometry, The Ohio State University (Fig. 2).Fig. 4.: Jay Enoch (1929–2025) Dean of the School of Optometry, University of California, Berkeley 1980–1992.Fig. 5.: Jay Enoch inspecting a laboratory set-up he designed to measure hyperacuity as a function of age in Berkeley, 1982.

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• Retinal Images with Catenary-Curved Contact Lenses [Letter]

  Clinical ophthalmology · 2025-12-01

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  The recent publication of a clinical trial of lenses with catenary curved power profile by Tuan et al 1 is an example of expandedfocus contact and intra-ocular lenses.The report is rare in that it includes the actual curvature specification, which allows independent evaluation of their diffraction-mandated resolution limit.Using the computational approach to the retinal image light distribution that had been applied to other non-traditional surface configurations, 2 this problem is explored here.After converting the curvatures to phase deviations of the wavefront converging on the retina, the diffraction image on the retina was calculated for monochromatic light, a round pupil of 4mm, and defocus in half-diopter steps from -1D to +4D, ie, target distances from 1m virtual to 25 cm real.To relate this information to the clinical reports, the computed point-spread functions were used to derive the light spread across the width of a 2 arcmin bright bar, the basic component of 20/40 (0.3 logMAR) letters on visual acuity charts.Because of its easy visualization of how defocus degrades the image through contrast reduction and light spread, this is a good measure for comparing patient data with the best performance allowed by physical theory.Figure 1 is the computationally generated through-focus display in the -1D to +4 diopter target vergence range, sideby-side for three conditions: left, normal viewing (with a plane wavefront) and a 4mm pupil, middle, with the catenary-Figure 1 Through-focus depiction of computed light spread in the retinal image of a 2 arcmin-wide bright bar in aberration-free eye with monochromatic light, for (left) normal vision with plane wavefront and 4mm pupil diameter, (middle) wearing catenary -curved contact lens and 4mm pupil, and (right) catenary curved lens and 6 mm pupil.Target vergence from bottom up in diopter steps from -1D (1m virtual) to 4D (25cm real).

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• Immanuel Kant's Schema of object perception and cognition

  Perception · 2025-06-10

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  , Kant proposed a detailed system of mental processes and constructs that might lead to a person's perceiving and comprehending an object in the outside world. The diffuse and extended original, found largely impenetrable and hence neglected in most modern discourse, is here revisited and presented in an updated contemporary idiom, with the aim of showing some structure in the mental world that may serve as a counterpart to definable states of the real world when attempts are made to find correlations between the two.

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• Retinal image quality for multifocal lenses with on- and off-axis annular zones

  Biomedical Optics Express · 2024-05-01 · 3 citations

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  Multi-focal intra-ocular or contact lenses, intended to increase depth of focus, conventionally have annular zones of additional refractive power, generating wavefront rings of coaxial spherical surfaces. It is, however, possible to influence depth of focus by changing not only the curvature of the wavefront, i.e., refractive power, in the annulus, but also the tilt, i.e., circularly symmetrical linear radial deviation imposed on the spherical wavefront. Employing the example of a single annulus bifocal, retinal image light distributions in the two regimes are calculated, using standard diffraction theory. Four measures of retinal image quality in through-focus scans show that plus power additions and wavefront tilts operate almost interchangeably. In testing these lenses, attention needs to be paid to the detailed operating characteristics of measuring devices of the Shack-Hartmann type to ensure that their grain and precision is compatible with the framework of the analysis.

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• The concept of group and the theory of perception

  Vision Research · 2024-10-28 · 4 citations

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  Prompted by the title of Ernst Cassirer's 1944 essay, the origin of the idea of a Group theoretical approach, in the mathematical sense, in vision science is here explored, as well as the several ways in which its implementation had been attempted. That object recognition might proceed by a more generative approach rather than by separate individual cataloging had already been argued by Kant, and Cassirer examined how mathematical group theory might be called on for this purpose, in view of the success of its use in geometry and in the physical sciences. However, such a promise appears unlikely in view of the categorical differences between analysis of mental phenomena and of the physical world.

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• Gestalt theory in 20th-century history

  Journal of Vision · 2023-08-18 · 1 citations

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  During the century from the 1890 publication of Ehrenfels's proposition on Gestaltqualitäten to the 1989 dissolution of the European states governed by Marxist orthodoxy, Gestalt theory was drawn into the political fray in several ways. It was grotesquely misappropriated during the Nazi regime in support of race, territorial expansion, and war aims. On the other side, because it was seen as having a subjectivist taint, the Gestalt approach was anathema where dialectical materialist dogma reigned. In contrast, close reading of the seminal 1912 Wertheimer paper and the 1920 Köhler book reveals that the Gestalt founders' views accord well with current Gestalt research.

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• Multifocal contact lens myopia control: central and peripheral retinal image quality

  Clinical and Experimental Optometry · 2022-05-09 · 2 citations

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  CLINICAL RELEVANCE: That myopic defocus, even if restricted to the peripheral retina, inhibits eye growth in young monkey eyes has motivated the therapy of myopia control through multifocal contact lens wear in children. BACKGROUND: To understand how eye-length regulating mechanisms are triggered by light requires knowledge of retinal light spread. That is largely lacking for the multifocal contact lenses used in the therapy because empirical methods identifying just the defocus in dioptres are inadequate. METHODS: -cone phototransduction layer, offer estimates of retinal image spread for a range of viewing distances. RESULTS: Point- and edge-spread distributions of activation of phototransduction in the central retina show that the addition of multifocal zones produces some veiling for in-focus viewing and substantial improvement of image quality for near targets in the unaccommodated eye. These effects are much reduced in the retinal periphery. CONCLUSION: Whatever therapeutic value there is in prescribing multifocal contact lenses for myopia control, it is not particularly dependent on the precise configuration of the multifocal zones, nor can it be ascribed to changes in image quality specific to the retinal periphery; its origin is more likely less blur for near targets, reducing the stimulus to accommodation.

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• Preface

  Berghahn Books · 2022-12-08

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  Why would a nonagenarian survivor, at the tail end of one of the many closed chapters of Jewish history, want to sponsor continued concern with it?Here are two reasons for promoting scholarship of the place of Jews in academia, culture, arts, professions, and commerce in German-speaking lands in the era from Moses Mendelssohn to the Third Reich and its aftermath.To be sure, the conflagration ending the era, one of the basest moments in Western history, isn't about to be forgotten; the Holocaust promises to remain a permanent reminder of how even the most cultured of people can go off the rails.The aims here, however, are different.One of them is to celebrate the achievements when there was, albeit temporarily and uneasily, a confluence of two distinct cultural streams.Towering figures from Heinrich Heine to Franz Kafka, from Felix Mendelssohn to Kurt Weill, from Karl Marx to Walter Benjamin, from Sigmund Freud to Max Wertheimer, even in their time and certainly from the beginning of the twentieth century cannot be thought of as Jews outside German culture any more than as Germans who were not also Jews.One cannot factor out Jews from the world ranking reached by Berlin as a metropolis, by Göttingen as a center in the mathematical and physical sciences, or by Dessau as an indelible trendsetter in the decorative arts.And the disproportionate success, whatever the field they took up, by a whole generation of Jewish émigrés who had merely a pre-World War II German-language upbringing speaks volumes about the unfulfilled promise of roles in their original homeland had they not been expelled.A second aim for continuing and deepening the studies sponsored by the Leo Baeck Institute is an attempt to lay bare any fault lines that might have foreshadowed what happened from 1933 on.Even the most thorough knowledge of history does not imply the prediction of the future-the past is replayed in ever newer versions as both farce and tragedy.Nevertheless, knowing now how it all ended, could one have identified telling precursors?What were the premonitions that, if heeded, might have mitigated, perhaps even prevented, the catastrophe?As an example, the vivid discussions that I witnessed as a boy in Berlin between advocates for and against emigration to what was then Palestine-at a time when assimilation was no longer an option but the State of Israel still years ahead-pointed clearly to the ongoing dialogue between diaspora and Israel Jewry.

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Recent grants

• NIH Grant R01EY000220

  NIH · $343k · 1987

• NIH Grant R37EY000220

  NIH · $1.1M · 2000

Frequent coauthors

• C Wehrhahn

  Salk Institute for Biological Studies

  21 shared

• Bilge Sayim

  University of Bern

  17 shared

• Michael H. Herzog

  Herzog College

  17 shared

• Jason Ng

  16 shared

• Charles D. Gilbert

  Rockefeller University

  14 shared

• Suzanne P. McKee

  Smith-Kettlewell Eye Research Institute

  12 shared

• Sidney M. Blair

  12 shared

• F. W. Campbell

  11 shared

Education

• Ph.D., Physics - Physiological Optics

  Ohio State University

  1953

• B.Sc., Maths, Physiology

  University of Sydney

  1947

• A.S.T.C. (Hons), Optometry

  Sydney Technical College

  1943