Comparison of the Oblique Extraocular Muscles

Krewson, William E.

doi:10.1001/archopht.1944.00890090056007

Cited by 12 publications

(7 citation statements)

References 5 publications

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“…from origin to insertion. Robinson already knew that the muscles do not follow the shortest path over the eye in eye movements out of the plane of the muscle as Krewson (1950) had assumed. because that causes too much bridle effect and too much twist of the muscle at the insertion.…”

Section: R O B I N S O N ' S O R I G I N a L Modelmentioning

confidence: 99%

Robinson's Computerized Strabismus Model Comes of Age

Simonsz

Spekreijse

1996

Strabismus

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In this article we review our further development of D.A. Robinson's computerized strabismus model. First, an extensive literature study has been carried out to get more accurate data on the anatomy of the average eye and the eye muscles, and about how these vary with age and with refraction. Secondly, the force-length relations that represent the mechanical characteristics of the eye muscles in the model have been determined more accurately in vivo recently, and the model was changed accordingly. Thirdly, many parameters that were free in the original model and not derived from in vivo measurements were replaced by derivatives from in vivo measurements or made redundant. Fourthly, the ease of operation was improved greatly and the algorithms were made so much faster that a calculation for nine positions of gaze now takes ten seconds on a handheld HP 200LX Palmtop. The predictions of the model compared well with clinical results in horizontal muscle surgery, oblique muscle surgery, forced duction tests and abducens, oculomotor or trochlear palsies. Consequently, complex strabismus surgery in our clinic is now guided by the predictions of the computerized model.

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Section: R O B I N S O N ' S O R I G I N a L Modelmentioning

confidence: 99%

Robinson's Computerized Strabismus Model Comes of Age

Simonsz

Spekreijse

1996

Strabismus

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“…A first approach for developing a mathematical model of the human eye was made by Krewson [2]. However, Krewson's model was just a geometrical model of the human eye which was later picked up and modified by Robinson [3].…”

Section: Methods and Modelsmentioning

confidence: 99%

Construction and application of an object-oriented computer model for simulating ocular positioning defects

Buchberger

Kaltofen

Priglinger

et al. 2003

Spektrum Augeheilkd

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Purpose: The goal of this paper is to give an overview of the latest developments in the construction and application of our interactive diagnostic software system for simulating ocular positioning defects.Methods: Object-oriented design techniques in the field of Software Engineering were used to build component based abstractions of our biomechanical model. Our biomechanical model is comprised of geometric representation, muscle force simulation and a kinematical model, enabling interactive substitution of system behavior. Therefore, our system is ideal for training and education purposes, since different model predictions can be evaluated on demand.Results: The implementation of our model is partially based on the work from J. Porrill, P. A. Warren and P. Dean. However, modifications to system behavior and mathematical representation of different types of models were applied. This paper gives a detailed explanation of these modifications, including implementation of rotations using quaternion representation, deployment of two different optimization algorithms for solving the forward and the inverse kinematics and adjustment of these calculations to geometrical properties of the biomechanical model. Model predictions were compared to basic clinical experience and other existing implementations.Conclusions: Finally, this paper gives an outlook on future developments and applications in training and education, extending our system towards an authoring tool, giving the user the possibility to illustrate pathologies and calculations. Moreover, we indent the separation of the "mathematical" kernel from the rest of the system in order to enable the development of clients which can remotely connect to the kernel and use it exclusively for performing calculations. Formulierung eines objektorientierten Computermodells zur Simulation von Augen -m o t i l i t ä t s s t ö r u n g e nZusammenfassung. Hintergrund: Diese Arbeit soll einen kurzen Überblick über die aktuellsten Entwicklungen am computerunterstützten Software System SEE++, basierend auf den Forschungsergebnissen des Projektes SEE-KID, geben. Methode: Unter Verwendung von objektorientierten Designtechniken im Bereich des Software-Engineering, wurde ein komponentenorientiertes, biomechanisches Modell des menschlichen Auges entwickelt. Dieses Modell setzt sich aus geometrischen Repräsentationen, Simulation von Muskel -k r ä f t e n , sowie der Definition eines darauf aufbauenden kinematischen Modells zusammen. Dadurch wurde eine interaktive Austauschbarkeit von z. B. verschiedenen geometrischen Modellen, während der Laufzeit des Systems erreicht, wodurch das SEE++ System eine idealen Ergänzung für Lehre, Ausbildung und Klinik darstellt. Ergebnisse: Die Implementierung des hier beschriebenen geometrischen Modells basiert im wesentlichen auf Vorarbeiten von J. Porrill, P. A. Warren und P. Dean. Dennoch wurden einige Adaptierungen in der mathematischen Definition sowie im Modellverhalten durchgeführt. Diese Arbeit gibt einen detaillierten Überblick über die Formulieru...

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“…Salzmann, quoted by Whitnall and Fuchs, quoted by Berens, 1943, stated that the line of insertion often showed gross irregularities, yet Howe, quoted by Krewson (1944), found its site almost constant. Fink, 1947, found insertional variations' of the inferior oblique muscle to be second only to those of the superior oblique muscle.…”

Section: Approach To Insertion Of' the Inferior Oblique Musclementioning

confidence: 98%

“…Though the majority of observers class the inferior oblique muscle as an abductor, Krewson (1944) recently drew attention to Volkmann's measurements which suggested that it was an adductor. He found that the muscle passed anterior to the vertical axis.…”

Section: Functions Of the Inferior Oblique Musclementioning

confidence: 99%

Sidelights on the Inferior Oblique Muscle

Anderson¹

1948

British Journal of Ophthalmology

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as is the performance of the visual tasks considered in this paper. Nevertheless, visual efficiency appears to come to! its maximum in early adulthood, and, thereafter, to fall off at a greater rate than we realise. This is in keeping with other findings concerning ageing. For example, Bouma1 has shown that contrast sensitivity is a function of age, and that it diminishes from the mid-twenties onwards; Mann and Sharpley2 have found there is a tendency for the rod field of the dark-adapted eye to contract with advancing age, this tendency becoming apparent at about the age of 30 years; and it has been shown that manual motility begins to decline in the late twenties3. Probably many accidents should be attributed to the slowing down of vision as age advances, and it is well known that dissatisfaction with standards of artificial lighting commonly found in workplaces is most prevalent among middleaged and elderly workers. The general tendency for visual performance to decline from a fairly early age, which, in spite of the few subjects studied, is so consistently shown by the results presented in this paper, is certainly subject to individual exceptions. Indeed, individually, some of the subjects of these experiments showed different rates of decline, and probably began their decline at different, though not widely different, ages.

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Comparison of the Oblique Extraocular Muscles

Cited by 12 publications

References 5 publications

Robinson's Computerized Strabismus Model Comes of Age

Robinson's Computerized Strabismus Model Comes of Age

Construction and application of an object-oriented computer model for simulating ocular positioning defects

Sidelights on the Inferior Oblique Muscle

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