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Articles 631 - 660 of 716

Full-Text Articles in Optometry

Macular Pigment And Its Contribution To Visual Performance And Experience, James Loughman, Peter Davison, John Nolan, Mukunda Akkali, Stephen Beatty Jan 2010

Macular Pigment And Its Contribution To Visual Performance And Experience, James Loughman, Peter Davison, John Nolan, Mukunda Akkali, Stephen Beatty

Articles

There is now a consensus, based on histological, biochemical and spectral absorption data, that the yellow colour observed at the macula lutea is a consequence of the selective accumulation of dietary xanthophylls in the central retina of the living eye. Scientifi c research continues to explore the function(s) of MP in the human retina, with two main hypotheses premised on its putative capacity to (1) protect the retina from (photo)-oxidative damage by means of its optical fi ltration and/or antioxidant properties, the so-called protective hypothesis and (2) infl uence the quality of visual performance by means of selective short wavelength …

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Macular Pigment Optical Density In An Aging Irish Population: The Irish Longitudinal Study On Ageing, John Nolan, Roseanne Kenny, Claire O'Regan, Hilary Cronin, James Loughman, Eithne Connolly, Patricia Kearney, Stephen Beatty Jan 2010

Macular Pigment Optical Density In An Aging Irish Population: The Irish Longitudinal Study On Ageing, John Nolan, Roseanne Kenny, Claire O'Regan, Hilary Cronin, James Loughman, Eithne Connolly, Patricia Kearney, Stephen Beatty

Articles

Purpose: The 3 carotenoids lutein, zeaxanthin, and meso-zeaxanthin, which account for the ‘yellow spot’ at the macula and which are referred to as macular pigment (MP), are believed to play a role in visual function and protect against age-related macular degeneration (AMD) via their optical and antioxidant properties. This study was undertaken to compare MP optical density (MPOD) in a population aged ≧50 years with MPOD values from a normative database of subjects aged 18–60 years. Methods: Seventy-nine subjects were recruited into this pilot study (The Irish Longitudinal Study on Ageing-TILDA). MPOD was measured using heterochromatic flicker photometry. Retinal fundus …

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Changes In Intraocular Pressure And Anterior Segment Morphometry After Uneventful Phacoemulsification Cataract Surgery, J. Dooley, S. Charalampidou, A. Malik, James Loughman, L. Molloy, S. Beatty Jan 2010

Changes In Intraocular Pressure And Anterior Segment Morphometry After Uneventful Phacoemulsification Cataract Surgery, J. Dooley, S. Charalampidou, A. Malik, James Loughman, L. Molloy, S. Beatty

Articles

Purpose To study changes in anterior segment morphometry after uneventful phacoemulsification cataract surgery, and to investigate whether there is a relationship between any observed changes and intraocular pressure (IOP) reduction after the procedure. Methods The anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), central corneal thickness (CCT), and IOP were measured in 101 non-glaucomatous eyes before and after uneventful phacoemulsification cataract surgery. Results After cataract surgery, the mean ACD, ACV, and ACA values increased by 1.08mm, 54.4mm3, and 13.11, respectively, and the mean IOP (corrected for CCT) decreased by 3.2mmHg. The predictive value of a previously …

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Macular Pigment And Its Contribution To Visual Performance And Experience [El Pigmento Macular Y Su Contribución Al Rendimiento Y Experiencia Visuals], James Loughman, Peter Davison, John M. Nolan, Mukunda C. Akkali, Stephen Beatty Jan 2010

Macular Pigment And Its Contribution To Visual Performance And Experience [El Pigmento Macular Y Su Contribución Al Rendimiento Y Experiencia Visuals], James Loughman, Peter Davison, John M. Nolan, Mukunda C. Akkali, Stephen Beatty

Articles

There is now a consensus, based on histological, biochemical and spectral absorption data, that the yellow colour observed at the macula lutea is a consequence of the selective accumulation of dietary xanthophylls in the central retina of the living eye. Scientific research continues to explore the function(s) of MP in the human retina, with two main hypotheses premised on its putative capacity to (1) protect the retina from (photo)-oxidative damage by means of its optical filtration and/or antioxidant properties, the so-called protective hypothesis and (2) influence the quality of visual performance by means of selective short wavelength light absorption prior …

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Overexpression Of Garp2 Increases Phototransduction Gain., Shanta Sarfare Jan 2010

Overexpression Of Garp2 Increases Phototransduction Gain., Shanta Sarfare

All ETDs from UAB

The cGMP-gated cation channel (CNG) in the rod photoreceptors is an essential component of phototransduction, and may have a role in maintaining structural integrity of the rod outer segment (ROS). The ß-subunit of the CNG channel (CNGB1) in the rod photoreceptors is comprised of an N-terminal glutamic acid-rich region (GARP') and a C-terminal channel-like region. Additionally, two soluble proteins GARP1 and GARP2 are alternatively spliced from the CNGB1 gene. Although GARPs are known to interact with other proteins in the rod photoreceptors, their role is currently unknown. To determine the role of GARP2 in the rod photoreceptors, we generated transgenic …

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Response Dynamics Of Retinal Ganglion And Early Visual Cortical Cells To Simulated Optical Blur, Michael Lance Risner Jan 2010

Response Dynamics Of Retinal Ganglion And Early Visual Cortical Cells To Simulated Optical Blur, Michael Lance Risner

All ETDs from UAB

Visual neurons are highly sensitive to changes in luminance around the mean level of light. The effects of changes in luminance contrast on the responses of retinal ganglion cells (RGCs) and V1 neurons have been extensively studied. Sharp transitions in luminance signify edges, which are key features in the visual environment. However, edges are rarely sharp and may be blurred. Edges are generally blurred because eyes have a restricted depth of field, sources of light are rarely point sources, edges are typically smooth, and rapid motion induces blur. The purpose of this research was to understand how RGCs and V1 …

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Exploration Of The Crosslinks Between Saccadic And Vergence Eye Movement Pathways Using Motor And Visual Perturbations, Kevin Paul Schultz Jan 2010

Exploration Of The Crosslinks Between Saccadic And Vergence Eye Movement Pathways Using Motor And Visual Perturbations, Kevin Paul Schultz

All ETDs from UAB

ANCOVA models to be non-orthogonal, we get similar results to the ANCOVA with

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Subconjunctivally Implantable Hydrogels With Degradable And Thermoresponsive Properties For Sustained Release Of Insulin To The Retina., Gauri P. Misra, Ravi S.J. Singh, Tomas S. Aleman, Samuel G. Jacobson, Thomas W. Gardner, Tao L. Lowe Nov 2009

Subconjunctivally Implantable Hydrogels With Degradable And Thermoresponsive Properties For Sustained Release Of Insulin To The Retina., Gauri P. Misra, Ravi S.J. Singh, Tomas S. Aleman, Samuel G. Jacobson, Thomas W. Gardner, Tao L. Lowe

College of Pharmacy Faculty Papers

The objective of this work is to develop subconjunctivally implantable, biodegradable hydrogels for sustained release of intact insulin to the retina to prevent and treat retinal neurovascular degeneration such as diabetic retinopathy. The hydrogels are synthesized by UV photopolymerization of N-isopropylacrylamide (NIPAAm) monomer and a dextran macromer containing multiple hydrolytically degradable oligolactate-(2-hydroxyetheyl methacrylate) units (Dex-lactateHEMA) in 25:75 (v:v) ethanol:water mixture solvent. Insulin is loaded into the hydrogels during the synthesis process with loading efficiency up to 98%. The hydrogels can release biologically active insulin in vitro for at least one week and the release kinetics can be modulated by varying …

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Gender And Ovarian Hormone Effects On The Relative Contribution Of Chromaticity To Brightness, Brian Keith Foutch Oct 2009

Gender And Ovarian Hormone Effects On The Relative Contribution Of Chromaticity To Brightness, Brian Keith Foutch

Dissertations

PURPOSE: The chromatic contribution to brightness perception was compared in males and females. METHODS: Direct brightness matching (DBM) and heterochromatic flicker photometry (HFP) were used to measure relative luminous efficiency, and DBM/HFP ratios were predicted to be higher for females than males on repeated measures and for each "primary" color. No gender differences were predicted in DBM or HFP measures. Within-females effects of estradiol (E2) and progesterone (PG) levels, contraceptive use, and menstrual cycle phase were also investigated. It was expected that E2 would directly predict DBM/HFP ratios and that PG would antagonize that relationship. Based on that prediction, DBM/HFP …

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Visionary Fall 2009, College Of Optometry Oct 2009

Visionary Fall 2009, College Of Optometry

Visionary

No abstract provided.

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Nsu College Of Optometry The Visionary Fall 2009 Vol 3 No 2, Nova Southeastern University Oct 2009

Nsu College Of Optometry The Visionary Fall 2009 Vol 3 No 2, Nova Southeastern University

Health Professions Divisions Course Catalogs and Course Descriptions

No abstract provided.

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Image Processing Of Oct Glaucoma Images And Information Theory Analysis, Shuting Wang Jan 2009

Image Processing Of Oct Glaucoma Images And Information Theory Analysis, Shuting Wang

Electronic Theses and Dissertations

Glaucoma is a group of optic nerve disease with progressive structural changes leading to loss of visual function. A careful examination and detection of changes in the optic nerve is the key to early diagnosis of glaucoma. Optical Coherence Tomography (OCT) is one of the known techniques of diagnosis of glaucoma. The patients' eyes are scanned and sub-surface images are captured from optical nerves. Captured OCT images usually suffer from noise and therefore image enhancement techniques can help doctors in better analysis of OCT images and diagnosis of glaucoma. In this thesis, we propose three successful algorithms for enhancing the …

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Visionary Spring 2009, College Of Optometry Jan 2009

Visionary Spring 2009, College Of Optometry

Visionary

No abstract provided.

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College Of Optometry Program Overview, Nova Southeastern University Jan 2009

College Of Optometry Program Overview, Nova Southeastern University

Health Professions Divisions Course Catalogs and Course Descriptions

No abstract provided.

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Modification Of Adenovirus Capsid Proteins For Gene Therapy Applications, Yizhe Tang Jan 2009

Modification Of Adenovirus Capsid Proteins For Gene Therapy Applications, Yizhe Tang

All ETDs from UAB

Adenovirus (Ad) is the most commonly used viral vector in gene therapy applications to date for a broad range of diseases. Although Ad-based viral vectors have many advantages in a variety of gene therapy designs, the commonly used adenoviral vectors have several key shortcomings. Those shortcomings include (1) inefficient transduction in cell types devoid of Ad’s native receptors and the incapability of gene delivery to targets behind physical barriers; (2) restricted accessibility to the central nerve system due to the existence of the blood-brain barrier (BBB); (3) lack of a useful strategy and platform to generate multi-functionality displaying Ad vectors …

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Comparisons Between Behavioral And Electrophysiological Measures Of Visual Function In Rodent Models Of Retinal Degeneration, Glen R. Rubin Jan 2009

Comparisons Between Behavioral And Electrophysiological Measures Of Visual Function In Rodent Models Of Retinal Degeneration, Glen R. Rubin

All ETDs from UAB

The critical flicker frequency (CFF) is the lowest frequency for which a flickering light appears steady. Measuring CFF indicates rod- and cone-driven function relative to light intensity. CFF can be measured by both electroretinogram (ERG) and behavior. We measured CFF in several rodent models of retinal degeneration in order to better characterize retinal degeneration and understand the functional implications of electrophysiological changes. We measured ERG CFF in RCS dystrophic (RCS-p+) and wild type (WT) rats at PN23, PN44, and PN64. ERG CFF data in RCS rats show significant early degeneration of the rods followed by cones. CFF was significantly lower …

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Patterns Of Differential Mrna And Protein Expression During Minus Lens Compensation And Recovery In Tree Shrew Sclera, Hong Gao Jan 2009

Patterns Of Differential Mrna And Protein Expression During Minus Lens Compensation And Recovery In Tree Shrew Sclera, Hong Gao

All ETDs from UAB

During the juvenile period of human development, an emmetropization mechanism uses visual signals to precisely guide the axial length elongation rate of the eyes to the optical power to keep the images in sharp focus. However, almost a third of the U.S. population develops axial myopia, in which the eye is elongated relative to the focal plane. The aims of the study were to examine 27 genes and 6 proteins in tree shrew sclera for potential differential expression patterns during minus lens compensation and dur-ing recovery. The study hypothesized that, in response to hyperopia produced by a -5 D lens, …

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Sustained Pupil Constriction Following Brief Light Exposure: Relation To Retinal Health, Laxmikanth Kankipati Jan 2009

Sustained Pupil Constriction Following Brief Light Exposure: Relation To Retinal Health, Laxmikanth Kankipati

All ETDs from UAB

The pupillary light reflex (PLR) is an indispensable clinical measure of visual, neurological and autonomic function which, until recently, was thought to be driven by only rods and cones. In 2000, a novel subset of retinal ganglion cells (RGCs) was discovered that express melanopsin and are intrinsically photosensitive (ipRGC). These ipRGCs contribute to the PLR and are responsible for the sustained pupilloconstriction observed following light offset (the post-illumination pupil response (PIPR)). The primary goal of this project was to examine the PIPR in a broad sample of the general human population. Using a newly-developed, wide-field optical system, we demonstrate that …

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Effects Of Daily Versus 30-Day Continuous Contact Lens Wear On Tear Cytokine Levels, Lucy Ebunoluwa Kehinde Jan 2009

Effects Of Daily Versus 30-Day Continuous Contact Lens Wear On Tear Cytokine Levels, Lucy Ebunoluwa Kehinde

All ETDs from UAB

The purpose of this investigation was to determine if 30 days of continuous contact lens wear produces a different ocular inflammatory response compared to 30 days of daily wear of Bausch & Lomb® PureVisionTM silicone hydrogel contact lenses. Eighty-five individuals wore these lenses for 30 days continuously in one eye and daily in the contralateral eye. Relative concentrations of 27 cytokines were measured in tear samples collected from the subjects using cytometric bead-based assays. Clinical tests were also conducted to correlate changes in cytokine levels to changes in clinical profiles. This study contributes to a greater understanding of the impact …

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Visionary 2008, College Of Optometry Aug 2008

Visionary 2008, College Of Optometry

Visionary

No abstract provided.

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Diagnostic Sensitivity/Specificity Of Preattentive Vision Tests In Glaucoma, James Loughman, Peter Davison, Daniel Ian Flitcroft Jul 2008

Diagnostic Sensitivity/Specificity Of Preattentive Vision Tests In Glaucoma, James Loughman, Peter Davison, Daniel Ian Flitcroft

Articles

Purpose. Damage to the nerve fiber layer or visual pathway might be expected to reduce the efficiency with which the visual system performs analysis of the ever-changing field of vision. The purpose of this article is to provide a further analysis of previously reported data (Loughman J, Davison P, Flitcroft I, Br J Ophthalmol 2007;91:1493-98.) to: (i) determine the sensitivity and specificity of a test of preattentive vision for glaucoma detection and (ii) provide a cutoff performance level that would serve to distinguish glaucoma in early cases. Methods. Three groups of observers (glaucoma, suspects, and normals) were examined, using computer-generated …

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Diagnostic Sensitivity/Specificity Of Preattentive Vision Tests In Glaucoma, James Loughman, Peter Davison, Daniel Ian Flitcroft Jul 2008

Diagnostic Sensitivity/Specificity Of Preattentive Vision Tests In Glaucoma, James Loughman, Peter Davison, Daniel Ian Flitcroft

Articles

Purpose. Damage to the nerve fiber layer or visual pathway might be expected to reduce the efficiency with which the visual system performs analysis of the ever-changing field of vision. The purpose of this article is to provide a further analysis of previously reported data (Loughman J, Davison P, Flitcroft I, Br J Ophthalmol 2007;91:1493–98.) to: (i) determine the sensitivity and specificity of a test of preattentive vision for glaucoma detection and (ii) provide a cutoff performance level that would serve to distinguish glaucoma in early cases. Methods. Three groups of observers (glaucoma, suspects, and normals) were examined, using computer-generated …

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Ocular Aberrations Wavefront Sensor In Clinical Application, Matthew Sheehan Apr 2008

Ocular Aberrations Wavefront Sensor In Clinical Application, Matthew Sheehan

Masters

A versatile Hartmann-Shack (HS) wavefront sensor (WFS) was designed and constructed. Its advantages include simultaneous pupil centre determination, off-axis capability, realtime data displays, and efficient lenslet sampling orientation. The instrument is compact and transportable, making it convenient for use in a clinical setting. Subject alignment is achieved by the use of a parallel channel that is recombined with the sensing channel to simultaneously image the external eye and the HS spots onto a single charge coupled device (CCD). The pupil centre is determined using this image of the eye, rather than the HS spots. Off-axis measurements are possible throughout an …

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Health Professions Division Catalog 2008-2009, Nova Southeastern University Jan 2008

Health Professions Division Catalog 2008-2009, Nova Southeastern University

Health Professions Divisions Course Catalogs and Course Descriptions

No abstract provided.

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College Of Optometry Program Overview, Nova Southeastern University Jan 2008

College Of Optometry Program Overview, Nova Southeastern University

Health Professions Divisions Course Catalogs and Course Descriptions

No abstract provided.

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Structural And Functional Properties Of Human Αa-Crystallin, Jose Mauro Chaves Jan 2008

Structural And Functional Properties Of Human Αa-Crystallin, Jose Mauro Chaves

All ETDs from UAB

The three specific aims of the project were: (1) compare effects of deamidation alone (i.e., αA-N101D, αA-N123D, αA-N101/123D), truncation alone (αA-NT mutant [deletion of residue no. 1-63], or αA-CT mutant [deletion of residue no. 140-173]), or both truncation plus deamidation on structural and functional properties of human lens αA-crystallin; (2) identify components of complexes in the water soluble-high molecular weight (WS-HMW) proteins of normal aging and cataractous human lenses; and (3) determine interactions among WT-αA, αA-NT and αA-CT crystallin species with filensin and phakinin (beaded filament proteins) in vitro. The comparative structural and functional differences between αA-deamidated and/or truncated mutants …

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Punctal Occlusion Impact On Tear Film Immuno-Regulatory Proteins Measured By Cytometric Bead-Based Assay, Martin W. Lafrance Jan 2008

Punctal Occlusion Impact On Tear Film Immuno-Regulatory Proteins Measured By Cytometric Bead-Based Assay, Martin W. Lafrance

All ETDs from UAB

PURPOSE: This study compares vendor reagents used for cytometric bead-based assay (CBA) of cytokines in human tears and validates a protocol for use in evaluating punctal occlusion, a treatment for keratoconjunctivitis sicca. It has been proposed that punctal occlusion may alter tear cytokine concentrations based on the facts that: (1) tear clearance, a measure of the balance between tear production and elimination, declines following occlusion and (2) reduced tear clearance and increased levels of pro-inflammatory tear cytokines are correlated in dry eye patients. This study compares tear clearance values and the level of 24 tear cytokines measured by CBA following …

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The Role Of Melanopsin Containing Retinal Ganglion Cells In The Pupillary Responses Of Human And Non-Human Primates, David H. Mcdougal Jan 2008

The Role Of Melanopsin Containing Retinal Ganglion Cells In The Pupillary Responses Of Human And Non-Human Primates, David H. Mcdougal

All ETDs from UAB

Historically, the characteristics of the light-evoked neural signals driving the human pupillary light reflex (PLR) have been poorly understood. It was assumed that these light signals originated exclusively from rod and cone photoreceptors, although the measured spectral sensitivity and response dynamics of the PLR were difficult to reconcile with the known properties of rods and cones. Recently, a novel photoreceptive cell class has been discovered in the mammalian retina. These unique retinal ganglion cells not only receive rod and cone inputs, but also express the photopigment melanopsin, and exhibit intrinsic photoresponses independent of rod and cone inputs. These intrinsically photosensitive …

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The Role Of Strychnine-Sensitive Nachrs In Rabbit Retinal Off Ganglion Cells, Jordan Michael Renna Jan 2008

The Role Of Strychnine-Sensitive Nachrs In Rabbit Retinal Off Ganglion Cells, Jordan Michael Renna

All ETDs from UAB

that when heteroskedasticity is present, but ignored, there is significant evidence to suggest

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Expression And Function Of Nicotinic Acetylcholine Receptors In Human Vascular Endothelial Cells, Ryan C. Splittgerber Jan 2008

Expression And Function Of Nicotinic Acetylcholine Receptors In Human Vascular Endothelial Cells, Ryan C. Splittgerber

All ETDs from UAB

Neuronal nicotinic acetylcholine receptors (nAChRs) are widely expressed in neural and non-neural tissues and have been reported to play a role in neovascularization and vascular diseases of the eye, specifically age-related macular degeneration (ARMD). However, the subunit composition of functional nAChRs, their mechanisms of action, and the downstream signaling pathways in non-neuronal tissues are not well understood. Since some nAChR subtypes have high Ca2+ permeability, we investigated the possible role of Ca2+ in activating signaling cascades that underlie the affects of nAChR activation in Human Dermal Microvascular Endothelial Cells (HDMECs). RT-PCR experiments revealed message for nearly all of the known …

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