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J Neurophysiol 2020 Jun 3. Epub 2020 Jun 3.

Institut für Neuroinformatik, Ruhr-Universität Bochum, Germany.

Conventional explanations of the vestibulo-ocular reflex (VOR), eye and head movements are re-visited by considering two alternative frameworks addressing the question of how the brain controls motor actions. Traditionally, biomechanical and/or computational frameworks reflect the views of several prominent scholars of the past, including Helmholtz and von Holst who assumed that the brain directly specifies the desired motor outcome and uses efference copy to influence perception. However, empirical studies resulting in the theory of referent control of action and perception (an extension of the equilibrium-point hypothesis) revealed that direct specification of motor outcome is inconsistent with non-linear properties of motoneurons and with the physical principle that the brain can control motor actions only indirectly, by changing or maintaining the values of neurophysiological parameters that influence, but can remain independent of, biomechanical variables. Read More

J Binocul Vis Ocul Motil 2020 May 15:1-3. Epub 2020 May 15.

Division of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel.

: Understanding the primary, secondary and tertiary actions of the vertical recti and oblique muscles is important in the diagnosis of various types of strabismus (superior oblique palsy, A- and V-patterns). Unfortunately, learning these actions can be very challenging. We designed a visual memory tool, and assessed its usefulness for medical students. Read More

Invest Ophthalmol Vis Sci 2019 12;60(15):5052-5058

Eidactics and The Strabismus Research Foundation, San Francisco, California, United States.

Purpose: The discovery of extraocular muscle (EOM) pulleys resolved long-standing issues in oculomotor physiology, revived interest in EOM function generally, and led to several new theories. We describe the pulley concept of Miller and Demer (M-D Pulleys) and briefly review evidence, distinguishing this well-supported notion from the Active Pulley Hypothesis (APH) and the EOM Compartments hypothesis, and critically reviewing the methodologies and evidence on which the latter are based.

Methods: We analyze evidence on mechanical independence of individual EOM fibers, implications of nerve tracing for functional independence of EOM layers and compartments, validity of image-based methods of assessing EOM contraction, and data analysis issues. Read More

PLoS One 2018 7;13(2):e0192214. Epub 2018 Feb 7.

Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan, United States of America.

Insulin-like growth factors (Igfs) are key regulators of key biological processes such as embryonic development, growth, and tissue repair and regeneration. The role of Igf in myogenesis is well documented and, in zebrafish, promotes fin and heart regeneration. However, the mechanism of action of Igf in muscle repair and regeneration is not well understood. Read More

Int Ophthalmol 2018 Dec 26;38(6):2451-2462. Epub 2017 Oct 26.

Optometry Research Group (GIO), Optics, Optometry and Vision Sciences Department, University of Valencia, C/Dr. Moliner, 50, 46100, Burjassot, Spain.

Purpose: The aim of this pilot study was to evaluate a new semiautomatic procedure to assess in vivo changes in the crystalline lens and ciliary muscle during accommodation.

Methods: A total of 14 subjects were divided into two groups, young (aged between 20 and 25 years) and adult (aged between 35 and 40 years), and measured with an anterior segment optical coherence tomography. A semiautomatic procedure was implemented to measure the central lens thickness (CLT), anterior lens radius (ALR) and the ciliary muscle area (CMA) for the unaccommodated eye and for a vergence of - 3. Read More

Acta Psychol (Amst) 2017 Oct 21;180:130-136. Epub 2017 Sep 21.

Würzburg University, Germany.

While there is ample evidence that actions are guided by anticipating their effects (ideomotor control) in the manual domain, much less is known about the underlying characteristics and dynamics of effect-based oculomotor control. Here, we address three open issues. 1) Is action-effect anticipation in oculomotor control reflected in corresponding spatial saccade characteristics in inanimate environments? 2) Does the previously reported dependency of action latency on the temporal effect delay (action-effect interval) also occur in the oculomotor domain? 3) Which temporal effect delay is optimally suited to develop strong action-effect associations over time in the oculomotor domain? Participants executed left or right free-choice saccades to peripheral traffic lights, causing an (immediate or delayed) action-contingent light switch in the upper vs. Read More

J Neurophysiol 2017 12 13;118(6):3175-3193. Epub 2017 Sep 13.

Washington National Primate Research Center, University of Washington, Seattle, Washington.

In pattern strabismus the horizontal and vertical misalignments vary with eye position along the orthogonal axis. The disorder is typically described in terms of overaction or underaction of oblique muscles. Recent behavioral studies in humans and monkeys, however, have reported that such actions are insufficient to fully explain the patterns of directional and amplitude disconjugacy of saccades. Read More

J Electromyogr Kinesiol 2016 Jun 8;28:23-30. Epub 2016 Mar 8.

Department of Biology Science and Technology, National Chiao Tung University, Hsinchu, Taiwan; Institute of Physics, Academia Sinica, Taipei, Taiwan. Electronic address:

Upper eyelid movement depends on the antagonistic actions of orbicularis oculi muscle and levator aponeurosis. Blepharoptosis is an abnormal drooping of upper eyelid margin with the eye in primary position of gaze. Transconjunctival incisions for upper eyelid ptosis correction have been a well-developed technique. Read More

J Neurophysiol 2016 Jan 4;115(1):370-8. Epub 2015 Nov 4.

Stein Eye Institute and Department of Ophthalmology, David Geffen Medical School, University of California, Los Angeles, California; and Department of Neurology, David Geffen Medical School, University of California, Los Angeles, California

Anatomical studies demonstrate selective compartmental innervation of most human extraocular muscles (EOMs), suggesting the potential for differential compartmental control. This was supported by magnetic resonance imaging (MRI) demonstrating differential lateral rectus (LR) compartmental contraction during ocular counterrolling, differential medial rectus (MR) compartmental contraction during asymmetric convergence, and differential LR, inferior rectus (IR), and superior oblique (SO) compartmental contraction during vertical vergence. To ascertain possible differential compartmental EOM contraction during vertical ductions, surface coil MRI was performed over a range of target-controlled vertical gaze positions in 25 orbits of 13 normal volunteers. Read More

J Neurophysiol 2015 Apr 14;113(7):2150-63. Epub 2015 Jan 14.

Department of Ophthalmology, David Geffen Medical School, University of California, Los Angeles, California; and.

Vertical fusional vergence (VFV) normally compensates for slight vertical heterophorias. We employed magnetic resonance imaging to clarify extraocular muscle contributions to VFV induced by monocular two-prism diopter (1.15°) base-up prism in 14 normal adults. Read More

Brain Behav Evol 2014 24;83(2):162-75. Epub 2014 Apr 24.

Department of Biology II, Ludwig Maximilians University Munich, Planegg, Germany.

Developmental and evolutionary data from vertebrates are beginning to elucidate the origin of the sensorimotor pathway that links gravity and motion detection to image-stabilizing eye movements--the vestibulo-ocular reflex (VOR). Conserved transcription factors coordinate the development of the vertebrate ear into three functional sensory compartments (graviception/translational linear acceleration, angular acceleration and sound perception). These sensory components connect to specific populations of vestibular and auditory projection neurons in the dorsal hindbrain through undetermined molecular mechanisms. Read More

Exp Brain Res 2013 Oct 14;230(3):291-300. Epub 2013 Aug 14.

UCL Institute of Cognitive Neuroscience, 17 Queen Square, London, WC1N 3AR, UK,

The desire to increase rewards and minimize punishing events is a powerful driver in behaviour. Here, we assess how the value of a location affects subsequent deployment of goal-directed attention as well as involuntary capture of attention on a trial-to-trial basis. By tracking eye position, we investigated whether the ability of an irrelevant, salient visual stimulus to capture gaze (stimulus-driven attention) is modulated by that location's previous value. Read More

Can J Ophthalmol 2013 Aug;48(4):292-9

Department of Ophthalmology, Ivey Eye Institute, University of Western Ontario, London, Ont., Canada.

Objective: To determine whether surgery to correct decompensated exotropia in adulthood had an impact on common visually guided manual tasks in the postoperative period.

Design: Case report.

Participants: Three adult patients with long-standing strabismus. Read More

Radiographics 2013 Jan-Feb;33(1):47-59

Department of Radiology, Seoul National University Bundang Hospital, 166 Gumi-ro, Bundang-gu, Seongnam-si, Gyeonggi-do 436-707, Korea.

Horizontal eye movements are conducted by the medial rectus and the lateral rectus muscles, which are innervated by the oculomotor nerve (cranial nerve III) and the abducens nerve (cranial nerve VI), respectively. The oculomotor and the abducens nuclei are interconnected by a tract in the brainstem named the medial longitudinal fasciculus (MLF). Through the MLF, the actions of the oculomotor and the abducens nuclei are coordinated, generating conjugate horizontal eye movements. Read More

Invest Ophthalmol Vis Sci 2012 Dec 19;53(13):8414-23. Epub 2012 Dec 19.

Department of Ophthalmology, Jules Stein Eye Institute, Los Angeles, California 90095-7002, USA.

Purpose: Intramuscular innervation of horizontal rectus extraocular muscles (EOMs) is segregated into superior and inferior (transverse) compartments, while all EOMs are also divided into global (GL) and orbital (OL) layers with scleral and pulley insertions, respectively. We sought evidence of potential independent action by examining passive mechanical coupling between EOM compartments.

Methods: Putative compartments of each of the six whole bovine anatomical EOMs were separately clamped to a physiologically controlled, dual channel microtensile load cell (5-mN force resolution) driven by independent, high-speed, linear motors having 20-nm position resolution. Read More

PLoS Comput Biol 2012 17;8(5):e1002508. Epub 2012 May 17.

Radboud University Nijmegen Medical Centre, Donders Institute for Brain, Cognition, and Behaviour, Department of Cognitive Neuroscience, Section Biophysics, Nijmegen, The Netherlands.

A major challenge in computational neurobiology is to understand how populations of noisy, broadly-tuned neurons produce accurate goal-directed actions such as saccades. Saccades are high-velocity eye movements that have stereotyped, nonlinear kinematics; their duration increases with amplitude, while peak eye-velocity saturates for large saccades. Recent theories suggest that these characteristics reflect a deliberate strategy that optimizes a speed-accuracy tradeoff in the presence of signal-dependent noise in the neural control signals. Read More

Acta Ophthalmol 2012 Jun 23;90(4):e310-3. Epub 2012 Jan 23.

Hôpital Ophtalmique Jules Gonin, Lausanne University Ophthalmology Department, Lausanne, Switzerland.

Purpose: To elucidate the aetiology of congenital Brown syndrome.

Methods: Four consecutive patients diagnosed with unilateral congenital Brown syndrome had a comprehensive standardized ocular motility examination. Any compensatory head posture was measured. Read More

Neuropsychologia 2011 May 18;49(6):1605-10. Epub 2011 Feb 18.

Department of Cognitive Psychology, Vrije Universiteit, Van der Boechorststraat 1, 1081 BT Amsterdam, The Netherlands.

Humans tend to create and maintain internal representations of the environment that help guiding actions during the everyday activities. Previous studies have shown that the oculomotor system is involved in coding and maintenance of locations in visual-spatial working memory. In these studies selection of the relevant location for maintenance in working memory took place on the screen (selecting the location of a dot presented on the screen). Read More

Rev Laryngol Otol Rhinol (Bord) 2010 ;131(2):145-52

Clinique Tourny, 68 rue du Palais Gallien, 33000 Bordeaux, France.

Graves disease orbitopathy is a complex progressive inflammatory disease. Medical treatment remains in all cases the proposed treatment of choice. Surgical treatment by bone decompression can be considered as an emergency mainly in cases of optic neuropathy or ocular hypertension not being controlled medically or in post-traumatic exophthalmos stage. Read More

Graefes Arch Clin Exp Ophthalmol 2011 Jun 18;249(6):909-19. Epub 2011 Jan 18.

Directorate of Orthoptics and Vision Science, University of Liverpool, Thompson Yates Building, Liverpool, L69 3GB, UK.

Purpose: To compare the range of ocular rotations measured by Octopus versus Goldmann perimetry.

Methods: Forty subjects (20 controls and 20 patients with impaired ocular movements) were prospectively recruited, age range 21-83 years. Range of uniocular rotations was measured in six vectors corresponding to extraocular muscle actions: 0°, 67°, 141°, 180°, 216°, 293°. Read More

Invest Ophthalmol Vis Sci 2011 Apr 27;52(5):2830-6. Epub 2011 Apr 27.

Department of Ophthalmology, University ofCalifornia, Los Angeles, California, USA.

Purpose: It has been proposed that the lateral rectus (LR), like many skeletal and craniofacial muscles, comprises multiple neuromuscular compartments subserving different physiological functions. To explore the anatomic potential of compartmentalization in all four rectus extraocular muscles (EOMs), evidence was sought of possible regional selectivity in intramuscular innervation of all rectus EOMs.

Methods: Whole orbits of two humans and one macaque monkey were serially sectioned at 10 μm thickness and stained with Masson's trichrome. Read More

Invest Ophthalmol Vis Sci 2010 Sep 30;51(9):4612-7. Epub 2010 Apr 30.

Department of Ophthalmology, University of California, Los Angeles, Los Angeles, CA 90095-7002, USA.

Purpose: Skeletal and craniofacial muscles are frequently composed of multiple neuromuscular compartments that serve different physiological functions. Evidence of possible regional selectivity in LR intramuscular innervation was sought in a study of the anatomic potential of lateral rectus (LR) muscle compartmentalization.

Methods: Whole orbits of two humans and five macaque monkeys were serially sectioned at 10-microm thickness and stained with Masson trichrome. Read More

J Anat 2010 Apr 22;216(4):496-509. Epub 2010 Feb 22.

Division of Human Anatomy and Cell Biology, School of Biomedical Sciences, University of Liverpool, Liverpool, UK.

The spatial arrangement of the semicircular canals and extraocular muscles of the eye has been of considerable interest, particularly to researchers working on adaptations of the vestibulo-ocular reflex. Here we offer the first, extensive comparative analysis of the spatial relationships between each extraocular muscle and the canal providing its primary excitatory stimulus. The sample consisted of 113 specimens, representing 51 extant mammalian species. Read More

Alcohol Clin Exp Res 2009 Nov 10;33(11):1956-65. Epub 2009 Aug 10.

Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon, USA.

Introduction: Urocortin 1 (Ucn 1) is an endogenous peptide related to the corticotropin-releasing factor (CRF). Ucn 1 is mainly expressed in the perioculomotor area (pIII), and its involvement in alcohol self-administration is well confirmed in mice. In other species, the relationship between the perioculomotor Ucn 1-containing population of neurons (pIIIu) and alcohol consumption needs further investigation. Read More

Int Rev Neurobiol 2009 ;86:3-21

University of Pisa, Interdepartmental Research Centre E. Piaggio, School of Engineering, 56100 Pisa, Italy.

A great demand for brain-machine and, more generally, man-machine interfaces is arising nowadays, pushed by several promising scientific and technological results, which are encouraging the concentration of efforts in this field. The possibility of measuring, processing and decoding brain activity, so as to interpret neural signals, is often looked at as a possibility to bypass lost or damaged neural and/or motor structures. Beyond that, such interfaces currently show a potential for applications in other fields, space science being certainly one of them. Read More

J Neurosci 2009 Feb;29(7):2136-50

Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6074, USA.

In subjects trained extensively to indicate a perceptual decision with an action, neural commands that generate the action can represent the process of forming the decision. However, it is unknown whether this representation requires overtraining or reflects a more general link between perceptual and motor processing. We examined how perceptual processing is represented in motor commands in naive monkeys being trained on a demanding perceptual task, as they first establish the sensory-motor association and then learn to form more accurate perceptual judgments. Read More

Anat Sci Educ 2008 May-Jun;1(3):126-9

Department of Anatomy and Cell Biology, SUNY Downstate Medical Center, Brooklyn, New York 11203, USA.

The actions of the individual extraocular muscles are best explained to medical students in a lecture format by showing the relationship of each muscle to the axes of the globe and the walls of the bony orbit. The lateral and medial rectus muscles cross only the vertical axis, and consequently, cause only abduction and adduction, respectively. These muscles can be tested simply by asking the patient to abduct or adduct. Read More

Neurology 2007 Dec;69(24):E35-40

Department of Neurology, Rush University Medical Center, 1725 West Harrison Street, Suite 1106, Chicago, IL 60612, USA.

Ocular misalignment and ophthalmoparesis result in the symptom of binocular diplopia. In the evaluation of diplopia, localization of the ocular motility disorder is the main objective. This requires a systematic approach and knowledge of the ocular motor pathways and actions of the extraocular muscles. Read More

Semin Neurol 2007 Jul;27(3):244-56

Department of Neurological Sciences, Rush University, Chicago, Illinois 60612, USA.

Ocular misalignment and nystagmus result in the visual symptoms of binocular diplopia and oscillopsia, and are frequently encountered in neurological practice. Correct localization of the underlying problem is the first step to accurate diagnosis, and requires a systematic approach and knowledge of the ocular motor pathways and actions of the extraocular muscles. This article contains three segments: The first outlines the diagnostic approach with attention to fine historical and examination details helpful in localization; the second describes common localizations of diplopia including extraocular muscle, neuromuscular junction, cranial nerve and nuclei, and supranuclear structures with attention to examination features characteristic for each location; and the third describes the types of acquired nystagmus and their treatments. Read More

Oftalmologia 2005 ;49(4):3-10

Clinica de Oftalmologie--Spitalul Clinic de Urgentă Militar Central, Bucureşti.

The principles of surgery of the oblique muscles are different from those of the rectus muscles according to their anatomy and physiology. Their exposure is difficult as they are inserted on the sclera behind the equator and because they form an angle of 51s with the visual axis they have a triple action. The types of procedures one can practice on the oblique muscles are: weakening and strengthening of their actions. Read More

Invest Ophthalmol Vis Sci 2006 Jan;47(1):188-94

Department of Ophthalmology, University of California, Los Angeles, California, USA.

Purpose: Magnetic resonance imaging (MRI) was used to determine the effect of recessions and resections on horizontal extraocular muscle (EOM) paths and globe position.

Methods: Four adults with horizontal strabismus underwent contrast-enhanced, surface-coil MRI in central, secondary, and tertiary gazes, before and after horizontal EOM recessions and/or resections. EOM paths were determined from 2-mm thickness, quasicoronal MRI by analysis of cross-sectional area centroids in a normalized, oculocentric coordinate system. Read More

Brain 2005 Sep 29;128(Pt 9):2175-88. Epub 2005 Jun 29.

Departamento de Fisiología y Zoología, Universidad de Sevilla, Spain.

The question whether general tetanus arises from the independent sum of multiple local tetani or results from the actions of the transynaptic tetanus neurotoxin (TeNT) in higher brain centres remains unresolved. Despite the blood-borne dissemination of TeNT from an infected wound, the access to the central nervous system is probably prevented by the blood-brain barrier. However, several long-term sequelae (e. Read More

J Vis 2003 Dec 2;3(11):725-36. Epub 2003 Dec 2.

Human Factors Research and Technology Division, NASA Ames Research Center, Moffett Field, CA, USA.

A fundamental question in primate neurobiology is to understand to what extent motor behaviors are driven by shared neural signals that also support conscious perception or by independent subconscious neural signals dedicated to motor control. Although it has clearly been established that cortical areas involved in processing visual motion support both perception and smooth pursuit eye movements, it remains unknown whether the same or different sets of neurons within these structures perform these two functions. Examination of the trial-by-trial variation in human perceptual and pursuit responses during a simultaneous psychophysical and oculomotor task reveals that the direction signals for pursuit and perception are not only similar on average but also co-vary on a trial-by-trial basis, even when performance is at or near chance and the decisions are determined largely by neural noise. Read More

J Appl Physiol (1985) 2004 Apr 24;96(4):1541-54. Epub 2003 Oct 24.

División de Neurociencias, Universidad Pablo de Olavide, 41013-Sevilla, Spain.

Early compensatory mechanisms between eyelid and eye-retraction motor systems following selective nerve and/or muscle lesions were studied in behaving rabbits. Reflex and conditioned eyelid responses were recorded in 1). controls and following 2). Read More

Invest Ophthalmol Vis Sci 2002 Jul;43(7):2169-78

Department of Ophthalmology, Jules Stein Eye Institute, University of California Los Angeles, 100 Stein Plaza, Los Angeles, CA 90095-7002, USA.

Purpose: Connective tissue pulleys serve as functional mechanical origins of the extraocular muscles (EOMs) and are normally stable relative to the orbit during gaze shifts. This study evaluated pulley stability in incomitant strabismus.

Methods: Contiguous 2- or 3-mm thick magnetic resonance images (MRIs) perpendicular to the orbital axis spanned the anteroposterior extents of 12 orbits of six patients with incomitant strabismus. Read More

Quintessence Int 2001 Mar;32(3):232-4

Maxillofacial Department, General Peripheric Accidents Hospital (KAT), Kifissia, Athens, Greece.

Diplopia caused by local anesthesia at the superior posterior alveolar nerve for the removal of the maxillary third molar is a rare complication. The diplopia is due to facial palsy of the oculomotor muscles of the globe. This paper describes the case of a 22-year-old woman, in whom diplopia was observed after an overall uncomplicated removal of the semi-impacted third molar. Read More

Neuron 2002 Apr;34(2):317-25

Department of Physiology, Juntendo University, School of Medicine, 2-1-1 Hongo, Bunkyo-ku, 113-8421, Tokyo, Japan.

Complex learned motor sequences can be composed of a combination of a small number of elementary actions. To investigate how the brain represents such sequences, we devised an oculomotor sequence task in which the monkey had to choose the target solely by the sequential context, not by the current stimulus combination. We found that many neurons in the supplementary eye field (SEF) became active with a specific target direction (D neuron) or a specific target/distractor combination (C neuron). Read More

Binocul Vis Strabismus Q 2001 ;16(3):173-80

Instituto de Oftalmologia Pediatrica, Barcelona, Spain.

Purpose: To obtain objective information about the effects of different amounts and directions of superior oblique muscle (SO) recession, on its three force components: torsional (incyclotorsion), vertical (depression), and horizontal (abduction).

Methods: A well known Biomechanical Model of Ocular Motility (Orbit 1.8 Gaze Mechanics Simulation), was used to simulate different amounts of recession of the superior oblique muscle, along three different and commonly used axes of recession: a) along its anatomical path (the hypothetical line uniting the trochlea and the scleral insertion of the SO); b) anteroposteriorly on the nasal side of the superior rectus muscle (recession with posterior transposition); and c) straightforward nasal transposition around the globe. Read More

Behav Brain Res 2001 Aug;122(2):145-57

Motor Control Laboratory, ESPE Department, Arizona State University, P.O. Box 870404, Tempe, AZ 85287-0404, USA.

Two experiments were conducted in order to determine the patterns of transfer of visuomotor adaptation between arm and head pointing. An altered gain of display of pointing movements was used to induce a conflict between visual and somatosensory representations. Two subject groups participated in Experiment 1: group 1 adapted shoulder pointing movements, and group 2 adapted wrist pointing movements to a 0. Read More

J AAPOS 2001 Apr;5(2):76-81

Department of Ophthalmology, The Hospital for Sick Children, Toronto, Ontario, Canada.

Purpose: We previously reported an 8% incidence of double-bellied inferior oblique (IO) muscles at the surgical capture site (10-12 mm from insertion) in cadaveric specimens. This companion study sought to determine how often this anomaly is encountered at surgery for clinically overacting IO muscles and whether clinical findings or surgical outcomes in cases with double-bellied muscles differ from those with single-bellied muscles.

Methods: For 7 years we collected preoperative, intraoperative, and postoperative data on all patients for whom one surgeon performed primary IO weakening operations for overactions. Read More

Philos Trans R Soc Lond B Biol Sci 2000 Dec;355(1404):1685-754

Department of Neuroscience, University of Edinburgh, UK.

This article sets out to present a fairly comprehensive review of our knowledge about the functions of the receptors that have been found in the extraocular muscles--the six muscles that move each eye of vertebrates in its orbit--of all the animals in which they have been sought, including Man. Since their discovery at the beginning of the 20th century these receptors have, at various times, been credited with important roles in the control of eye movement and the construction of extrapersonal space and have also been denied any function whatsoever. Experiments intended to study the actions of eye muscle receptors and, even more so, opinions (and indeed polemic) derived from these observations have been influenced by the changing fashions and beliefs about the more general question of how limb position and movement is detected by the brain and which signals contribute to those aspects of this that are perceived (kinaesthesis). Read More

Ophthalmology 2000 Nov;107(11):1999-2005

Department of Ophthalmology, The Hospital for Sick Children and The University of Toronto, Toronto, Ontario, Canada.

Objective: To evaluate the reliability of strabismus assessment using telemedicine (TM) technology.

Design: Two prospective interobserver agreement studies. One study compared the agreement between a standard and a TM examination, whereas the other assessed agreement between two independent standard examinations. Read More

Neuroscience 1997 Aug;79(3):943-56

Centre for Neuroscience, University of Edinburgh, U.K.

Movements of the head and eyes are known to be intimately related. Eye position has also been shown to be closely related to the electromyographic activity of dorsal neck muscles; however, extraocular muscle proprioception has not generally been considered to play a part in the control of such movements. We have previously shown that, in the pigeon, imposed movements of one eye modify the vestibular responses of several dorsal neck muscles in ways that are dependent on stimulus parameters such as the amplitude and velocity of imposed eye movement. Read More

J Pediatr Ophthalmol Strabismus 1996 Jul-Aug;33(4):208-18

Jules Stein Eye Institute, Department of Ophthalmology, University of California, Los Angeles 90024-7002, USA.

Purpose: Magnetic resonance imaging (MRI) shows that the paths of rectus extraocular muscle bellies remain fixed in the orbit during large ocular rotations, and across large surgical transpositions of their insertions. This stability of muscle paths is due to their passage through pulleys which are coupled to the orbit and located in a coronal plane anterior to the muscle bellies near the equator of the globe. Autopsy studies have shown the pulleys to be fibroelastic sleeves consisting of dense bands of collagen and elastin, suspended from the orbit and adjacent extraocular muscle sleeves by bands of similar composition. Read More

Neuroscience 1995 Nov;69(2):671-83

Centre for Neuroscience, University of Edinburgh, U.K.

Recent physiological experiments in our laboratory suggest that extraocular muscle proprioceptive signals are involved in oculomotor control in the pigeon [e.g., Knox and Donaldson (1993) Proc. Read More

Vision Res 1994 Jul;34(13):1785-98

Department of Ophthalmology, Huddinge University Hospital, Karolinska Institute, Sweden.

Vertical saccadic movements recorded with electrooculography (EOG) and force development measured by means of a contact lens-strain gauge technique were investigated in 13 patients with a clinical diagnosis of unilateral superior oblique palsy (SOP) and 10 normal subjects. Upward and downward movements from the horizontal level to 5, 10 and 20 deg of deviation with monocular fixation were made in the 20 deg abduction and adduction fields of gaze. Peak velocity (Vp) and the ratio of downward over upward movement (VpD/U) of the paretic eye (PE) and the sound eye (SE) of the patients were compared with the values of the covered, non-fixating eye (CE) and the fixating eye (FE) of the normals respectively. Read More

Baillieres Clin Neurol 1993 Aug;2(2):191-225

Medical Research Council Anatomical Neuropharmacology Unit, Oxford, UK.

Studies of the visual system of the primate have taken two directions. One group of neurobiologists have studied the oculomotor system, while an entirely separate group have analysed sensory processing in the retinogeniculo-cortical circuits. However, the versatility and adaptability of the primate visual system is only possible because sensory and oculomotor processing are highly integrated. Read More

Surv Ophthalmol 1993 Jul-Aug;38(1):31-62

An accurate clinical evaluation of vertical diplopia is predicated upon meticulous history-taking, observations regarding the presence and pattern of an anomalous head position, and the analysis of several subjective and objective tests of extraocular muscle function. To reach a final diagnosis with minimum risk and expense to the patient the examiner must be familiar with the neuroanatomy of the supranuclear and infranuclear pathways which control the actions of the vertically-acting extraocular muscles, the clinical methods and pitfalls of a number of clinical techniques which are used to identify an underacting extraocular muscle, and the hallmark characteristics of a supranuclear, infranuclear and restrictive ophthalmopathy. Read More