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2 edition of Mechanisms of three dimensional ocular control as revealed in patients with skew deviation. found in the catalog.

Mechanisms of three dimensional ocular control as revealed in patients with skew deviation.

Maryam Fesharaki

Mechanisms of three dimensional ocular control as revealed in patients with skew deviation.

by Maryam Fesharaki

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Published .
Written in English


About the Edition

Our eyes rotate with 3 degrees of freedom---horizontally, vertically, and torsionally---but torsional control is poorly understood. We know that in many visual tasks torsion is not an independent variable, but is determined by horizontal and vertical eye position; this fact is called Donders" law. Specifically, torsion is a linear function of horizontal and vertical eye position; this is Listing"s law. I studied the mechanisms of these laws by recording 3-D ocular coordination in healthy subjects and in patients with an acquired oculomotor disorder called skew deviation. I found that both laws were broken in the acute stage of the disorder, and that both were later restored, though the linear function relating torsion to the other dimensions remained abnormal. These findings suggest that the neural mechanisms underlying Donders" and Listing"s laws are adaptive: they restore the laws when ocular control is disrupted by a central lesion.

The Physical Object
Pagination76 leaves.
Number of Pages76
ID Numbers
Open LibraryOL21218956M
ISBN 109780494273944

  When asked to compare two lateralized shapes for horizontal size, neglect patients often indicate the left stimulus to be smaller. Gainotti and Tiacci () hypothesized that this phenomenon might be related to a rightward bias in the patients' gaze. This study aimed to assess the relation between this size underestimation and oculomotor asymmetries. Eye movements were recorded while three Cited by: The range of fusion that could be obtained before binocular vision broke down was assessed using polarised vectographs. Each pupil was asked whether vision tended to become double when reading. Dynamic visual behaviour, ocular control, and associated postural compensation and muscular stress while actually reading were investigated.

Start studying Chapter 4. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Search. Gate-control theory. Impossible figures. Objects that can be represented in two-dimensional pictures but cannot exist in three-dimensional space. Just noticeable difference (JND). The three-dimensional head impulse test revealed residual posterior canal function in all patients with vertigo attacks (eight). The control patients had no residual canal function. Thus, residual vestibular function on the ipsilesional side may cause vertiginous Meniere attacks.

  Read the April 1, issue. Volume , Number 4. Ocular Dominance Columns and Their Development in Layer IV of the Cat's Visual Cortex: A Quantitative Study density were first noted at three weeks, and a pattern similar to that of the adult was reached by about six weeks of age. On the contralateral side the uniform .


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Mechanisms of three dimensional ocular control as revealed in patients with skew deviation by Maryam Fesharaki Download PDF EPUB FB2

The ocular tilt reaction and its associated skew deviation represent a fundamental pattern of eye-head coordination in the roll plane, 61, 64 The otolith-ocular response to rotation is impaired in patients with skew deviations due to brainstem lesions.

The ocular tilt reaction can be observed not only in patients with peripheral Cited by: This study was conducted to determine whether patients with skew deviation show the normal pattern of three-dimensional eye control called Listing's law, which specifies the eye's torsional angle.

The linear vestibulo-ocular reflex (LVOR) is mediated primarily by the otolith organs in the inner ear. Skew deviation is a vertical strabismus believed to be caused by imbalance of otolithic.

"Ocular Disease: Mechanisms and Management is invaluable in its emphasis on discussions of the pathophysiology of ocular disease.

It provides an excellent and up-to-date overview of ophthalmic pathophysiology and bridges the gap between Pages:   x - Lect 24 - Rolling Motion, Gyroscopes, VERY NON-INTUITIVE - Duration: Lectures by Walter Lewin. They will make you ♥ Physics. Recommended for you.

Arch Neurol. Mar;32(3) Ocular skew deviation. Analysis of cases. Keane JR. In patients with ocular skew deviation, the lesion was usually on the side of the lower eye, particularly when patients with internuclear ophthalmoplegia were excluded, but exceptions were sufficiently frequent to diminish the clinical lateralizing value of skew.

Pontine damage was most commonly Cited by:   DISCUSSION A skew deviation is a vertical misalignment of the eyes that is caused by damage to the otolithic input to the ocular motor nuclei.

When accompanied by binocular torsion, head tilt toward the hypotropic eye, and a tilt in the subjective visual vertical toward the lower (hypotropic) eye, it is termed the ocular tilt reaction. The side. METHODS: A day, randomized, investigator-masked, clinical trial involving patients with elevated intraocular pressure (IOP).

Study medications were instilled topically. Doses of %, %, or % AGN were given once daily for 3 weeks then twice daily for 1 week, and vehicle control or % timolol was given twice daily for 4 Cited by:   Skew Deviation Revisited Skew Deviation Revisited Brodsky, Michael C.; Donahue, Sean P.; Vaphiades, Michael; Brandt, Thomas Skew deviation is a vertical misalignment of the eyes caused by damage to prenuclear vestibular input to ocular motor nuclei.

The resultant vertical ocular deviation is relatively comitant in nature, and is usually seen in the context of brainstem or.

Patients with cerebellar damage may have a skew deviation that often changes sense with horizontal eye position (alternating skew deviation) (Versino et al.,Zee,Wong and Sharpe, ). The abducting eye is usually higher, producing a pattern of right hyperdeviation in right gaze and left hyperdeviation in left by: e CPA or labyrinthectomy Main Outcome Measure Complete neuro-opthalmologic examination including opticokinetic testing, confrontational visual field assessment, color plate, pupillary reflex, slit lamp examination, and head tilt test.

Results Four patients with residual hearing preoperatively developed skew deviation immediately after surgical intervention, including translabyrinthine (n = 1. position, whereas in patients with trochlear nerve palsy, it changed little between positions. Torsion was de-creased by 83% in patients with skew deviation, 2% in patients with trochlear nerve palsy, and 6% in healthy subjects(P).Similarly,verticalmisalignmentwas decreased by 74% in Cited by: The Development of Ocular Dominance Columns: Mechanisms and Models K.

Miller and M. Stryker Introduction The function of the visual cortex depends upon the precision with which its cells are connected to their inputs.

Such precise connections are fonned during nonnal development in. Three Dimension Tomography of Eye Structures by White Light Imaging Device (3D-WLT) The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S.

Federal Government. now extended to all three dimensions: eye movements were recorded while subjects actively oscillated their heads around the vertical, horizontal or sagittal axis atand Hz and fixated a point target. During voluntary head movements, the vestibule-ocular reflex makes a.

Patients with vestibular neuritis show spontaneous horizontal-torsional nystagmus beating away from the lesion side, Three-dimensional video-oculography is commonly used, which can measure the direction and slow-phase velocity of spontaneous nystagmus.

skew deviation, and ocular torsion. Ocular torsion can be determined on fundus photos. Comparision of Retinal Surgery by Three-dimensional Heads-up Display to the Standard Operating Microscope. observational study investigating a three dimensional heads up display for retinal surgery and comparing its outcomes and ease of use with the standard operative microscope.

Objective To investigate changes in ocular factors according to the binocular disparity in three-dimensional (3D) images and age after watching 3D display. Methods A total of 38 volunteers were enrolled, and they watched a 3D display with a 1° or 3° disparity for 30 min at an interval of 1 week.

The near point of accommodation (NPA), near point of convergence (NPC) and tear break-up time Cited by: 9. This popular manual introduces the organization and analysis of clinical optometric data used in writing prescriptions for glasses.

This edition has been greatly expanded to include new information on accommodative disorders and fixation disparity (among others). Case reports integrated throughout the text illustrate the management process. elevations, the three-dimensional (3D) angular rotation axis of the globe tilts by half the vertical eye eccentricity.

This phenomenon is named “half-angle rule” and is a consequence of Listing’s law. It was recently found that the ocular rotation axis during the horizontal vestibulo-ocular reflex (VOR) on a turntable also tilts in the direc.

We evaluated the effect of maintained gaze deviation on the displacement component of the oculogyral illusion (OGI). Whiteside, Graybiel, and Niven () proposed that the perception of an OGI was dependent upon the central monitoring of a fixation command needed to suppress vestibular nystagmus and maintain a retinally stable target.

By employing a procedure developed by Alexander Cited by: Airaksinen and colleagues18 examined RNFL photographs taken with a red-free filter in patients with glaucoma, ocular hypertension, and normal subjects in a masked fashion.

They identified RNFL defects in 48 of 51 glaucoma patients, 27 of 52 patients with ocular hypertension, and only 5 .Start studying Chapter 3 Review. Learn vocabulary, terms, and more with flashcards, games, and other study tools.

Search. The organization of sensations in three dimensions, even though the image on the eye's retina is two-dimensional. signals are sent to open or close those "gates" that control the neurological pathways for pain.

Cornea.