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Articles 1381 - 1390 of 1390

Full-Text Articles in Ophthalmology

Transcranial Magnetic Stimulation Of The Prefrontal Cortex Delays Contralateral Endogenous Saccades, Tony Ro, Avishai Henik, Liana Machado, Robert D. Rafal Jul 1997

Transcranial Magnetic Stimulation Of The Prefrontal Cortex Delays Contralateral Endogenous Saccades, Tony Ro, Avishai Henik, Liana Machado, Robert D. Rafal

Publications and Research

The contributions of the superior prefrontal cortex (SPFC) and the superior parietal lobule (SPL) in generating voluntary endogenous and reflexive visually guided saccades were investigated using transcranial magnetic stimulation (TMS). Subjects made choice saccades to the left or right visual field in response to a central arrowhead (endogenous go signal) or a peripheral asterisk (exogenous go signal) that were presented along with a single TMS pulse at varying temporal intervals. TMS over the SPFC increased latencies for saccades made in response to an endogenous go signal toward the contralateral hemifield. No effects were observed when the go signal was exogenous …

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Apparatus And Method For Restoring Eyelid Function, Robert S. Baker, Brian J. Willoughby, Robert R. Marshall Jun 1996

Apparatus And Method For Restoring Eyelid Function, Robert S. Baker, Brian J. Willoughby, Robert R. Marshall

Ophthalmology and Visual Science Faculty Patents

An apparatus is provided to restore eyelid function in a patient unable to voluntarily raise an eyelid. The apparatus includes a spiral torsion spring and pulley arrangement mounted in a housing that is implanted in the superior portion of the orbit of the eye. A wire connects the pulley to the eyelid. A spiral torsion spring provides the necessary spring force in tension to overcome the weight of the eyelid and draw the eyelid open. The natural muscles of eye closure are, however, sufficiently strong to overcome the spring tension thereby paying out wire from the pulley and closing the …

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Removal Of Extracellular Chloride Suppresses Transmitter Release From Photoreceptor Terminals In The Mudpuppy Retina., Wallace B. Thoreson, R . F. Miller May 1996

Removal Of Extracellular Chloride Suppresses Transmitter Release From Photoreceptor Terminals In The Mudpuppy Retina., Wallace B. Thoreson, R . F. Miller

Journal Articles: Ophthalmology

Removal of extracellular Cl- has been shown to suppress light-evoked voltage responses of ON bipolar and horizontal cells, but not photoreceptors or OFF bipolar cells, in the amphibian retina. A substantial amount of experimental evidence has demonstrated that the photoreceptor transmitter, L-glutamate, activates cation, not Cl-, channels in these cells. The mechanism for Cl-free effects was therefore reexamined in a superfused retinal slice preparation from the mudpuppy (Necturus maculosus) using whole-cell voltage and current clamp techniques. In a Cl-free medium, light-evoked currents were maintained in rod and cone photoreceptors but suppressed in horizontal, ON bipolar, and OFF bipolar cells. Changes …

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Sustained Release Drug Delivery Devices, Thomas J. Smith, Paul Ashton, Paul A. Pearson Jan 1995

Sustained Release Drug Delivery Devices, Thomas J. Smith, Paul Ashton, Paul A. Pearson

Ophthalmology and Visual Science Faculty Patents

A method and device for treating a mammalian organism to obtain a desired local or systemic physiological or pharmacological effect is provided. The method includes administering a sustained release drug delivery system to a mammalian organism in need of such treatment at an area wherein release of an effective agent is desired and allowing the effective agent to pass through the device in a controlled manner. The device includes an inner core or reservoir comprising the effective agent; a first coating layer, which is essentially impermeable to the passage of the effective agent; and a second coating layer, which is …

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Actions Of (1s,3r)-1-Aminocyclopentane-1,3-Dicarboxylic Acid (1s,3r-Acpd) In Retinal On Bipolar Cells Indicate That It Is An Agonist At L-Ap4 Receptors., Wallace B. Thoreson, R. F. Miller Jun 1994

Actions Of (1s,3r)-1-Aminocyclopentane-1,3-Dicarboxylic Acid (1s,3r-Acpd) In Retinal On Bipolar Cells Indicate That It Is An Agonist At L-Ap4 Receptors., Wallace B. Thoreson, R. F. Miller

Journal Articles: Ophthalmology

Metabotropic glutamate receptors (mGluRs) include receptors sensitive to L-2-amino-4-phosphonobutyrate (L-AP4) and 1S,3R-1-aminocyclopentane-1,3-dicarboxylic acid (1S,3R-ACPD). To determine whether 1S,3R-ACPD is an agonist at retinal L-AP4 receptors, whole cell voltage clamp recordings were obtained from mudpuppy ON bipolar cells in a superfused retinal slice and L-AP4 and 1S,3R-ACPD were bath applied. Both compounds evoked similar outward currents which reversed near 0 mV and were accompanied by an increased input resistance. Responses to both agonists washed out in parallel suggesting they act through the same second messenger pathway(s). Inhibitors of cGMP-PDE activity suppressed responses to both L-AP4 and 1SR,3RS-ACPD, suggesting that both compounds …

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A 5 Year Retrospective Case Study Of Penetrating Ocular Trauma At The Aga Khan University Hospital, Karachi, S Qarab Hasnain, Muzaffar Kirmani Aug 1991

A 5 Year Retrospective Case Study Of Penetrating Ocular Trauma At The Aga Khan University Hospital, Karachi, S Qarab Hasnain, Muzaffar Kirmani

Section of Ophthalmology

Ocular Trauma is an important cause of monocular visual impairment and blindness in younger age groups. We examined the cases of hospitalized ocular trauma from 1st January, 1985 through 30th July, 1990 using hospital medical records. The study comprised 27 patients (28 eyes), 51.8% of whom were under 16. The male-female ratio was 2.8:1. Right eye was more commonly involved (66.6%) and one patient had bilateral ruptured globes. Children at play were most vulnerable (33.3%) followed by road accidents which was the major cause (29.6%) in adults. Sixteen (64.0%) eyes suffered some complications and their mean duration of presentation after …

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The Effect Of Oxygen On Corneal Neovascularization, M. A. Culton, D. B. Chandler, A. D. Proia, D. W. Hickingbotham, G. K. Klintworth Jul 1990

The Effect Of Oxygen On Corneal Neovascularization, M. A. Culton, D. B. Chandler, A. D. Proia, D. W. Hickingbotham, G. K. Klintworth

Osteopathic Medicine, Jerry M. Wallace School of

Since tissue oxygen levels are believed to play a pivotal role in new vessel growth in several situations, we studied the effect of several oxygen concentrations (0, 10, 21, 50, 75, or 100%) on corneal vascularization induced in the rat by chemical cautery. We achieved this by perfusing known concentrations of oxygen through goggles fitted over both eyes of the rat after corneal cauterization. Neovascularization was measured in flat corneal preparations with India ink-filled vessels 4 days postcautery using computerized image analysis. The angiogenic response of rats whose eyes were continuously exposed to 0-75% oxygen were not significantly different from …

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The Effects Of Decreased Uncertainty And Telescopic Versus Full Field Training On The Useful Field Of View, Lauren M. Jackson Feb 1990

The Effects Of Decreased Uncertainty And Telescopic Versus Full Field Training On The Useful Field Of View, Lauren M. Jackson

Masters Theses & Specialist Projects

The “Useful Field of View” (UFOV) is the entire area in which information can be gathered without moving the eyes or head (Ball, Beard, Roenker, Miller & Griggs, 1998). Previous research has demonstrated that the UFOV shrinks with age (Scialfa, Kline & Lyman, 1987; Plude & Doussard-Roosevelt, 1987: Ball et al., 1988). With decrement in the UFOV, everyday activities, such as driving and walking can be limited. If the area in which information is received is smaller, then objects seem to appear suddenly and here is little time to react to them. One example of an everyday activity that would …

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Heterochromia Iridis From The Genetical Viewpoint, Richard Charles Suehr May 1940

Heterochromia Iridis From The Genetical Viewpoint, Richard Charles Suehr

Bachelors’ Theses

It is intended in this paper to present the published data obtainable; to report original data; to analize this data; and to try to establish some law of heredity by which the phenomenon of Heterochromia Iridis is transmitted from generation to generation.

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Proptosis Of Eye: An Atypical Presentation Of Prostatic Malignancy., Amna Amjad, Asif Husain Osmani, Ghulam H Mar 205

Proptosis Of Eye: An Atypical Presentation Of Prostatic Malignancy., Amna Amjad, Asif Husain Osmani, Ghulam H

Section of Pulmonary & Critical Care

Orbital metastasis is a rare occurrence found only in about 3 - 10% of all prostate cancers. A 72 years male presented with proptosis of the left eye associated with pain, blurred vision and frequent headaches for the past 8 months. Past medical history had symptoms of bladder outflow obstruction for 3 years. MRI brain and orbit with contrast was consistent with a large soft tissue mass in the left frontal region. The mass was surgically excised in order to achieve palliation. Histopathology revealed poorly differentiated malignant neoplasm with immunohistochemistry favoring metastatic prostate carcinoma. Postoperative radiotherapy was administered with a …

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