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Full-Text Articles in Optometry
Modulation Of The Unfolded Protein Response To Delay Apoptosis In An Autosomal Dominant Retinitis Pigmentosa Animal Model, Yogesh Bhootada
Modulation Of The Unfolded Protein Response To Delay Apoptosis In An Autosomal Dominant Retinitis Pigmentosa Animal Model, Yogesh Bhootada
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Retinitis pigmentosa (RP) is a group of retinal degenerative diseases characterized by the loss of rod photoreceptor cells that can be followed by cone degeneration eventually culminating in total photoreceptor cell loss. This disease affects approximately 1.5 million people worldwide and can be transmitted in an autosomal dominant (ADRP) manner accounting for nearly 30% of all RP cases. Dominant rhodopsin mutations have been divided into class I and class II based on the folding of rhodopsin protein, thermal stability, and chromophore regeneration. A threonine-17-methionine (T17M) mutation in rhodopsin is a class II mutation, characterized by a thermal instability/folding defect and …
Gene Expression Signatures In Tree Shrew Retina, Rpe, And Choroid During Experimental Myopia And Recovery, Li He
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During the development of induced myopia and recovery, the emmetropization mechanism is stimulated to modulate ocular growth. Emmetropization signals originate in the retina, are transmitted and transformed by retinal pigment epithelium (RPE) and choroid, and reach sclera to induce tissue remodeling. Induced myopia occurs in response to myopiagenic stimuli - minus lens, form deprivation, and darkness - (three GO conditions) which increase ocular elongation; recovery from lens-induced myopia (STOP) occurs when minus-lens wear is discontinued after complete compensation, slowing ocular elongation. This dissertation examined gene expression signatures in the retina, RPE, and choroid under GO and STOP conditions to examine …
Gene Expression Signatures In Tree Shrew Sclera In Different Visual Conditions, Lin Guo
Gene Expression Signatures In Tree Shrew Sclera In Different Visual Conditions, Lin Guo
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The sclera is a target tissue that receives signals that are initiated in the retina, cascade through retinal pigment epithelium (RPE) and choroid, and cause scleral extra cellular matrix remodeling. Biomechanical alterations of the sclera are produced by these biochemical changes, and in turn control the axial length of the eye. This dissertation project examined scleral gene expression changes in mRNA level of juvenile tree shrews. Three specific aims were investigated: specific aim one tested the hypothesis that three different GO visual conditions that all produce axial elongation and myopia: minus-lens wear, form deprivation, and continuous darkness, will produce similar …
Effects Of Nicotine On The Human Visual System: 1) Color Perception; 2) Processing At The Cortical Level, Naser T. Naser
Effects Of Nicotine On The Human Visual System: 1) Color Perception; 2) Processing At The Cortical Level, Naser T. Naser
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The visual system is sensitive to various types of chemical substances, including nicotine. Nicotinic acetylcholine receptors (nAChRs) are found in the nervous system, including the retina. These receptors play a role in modulating signals within the visual system. It has been shown that smoking affects color vision, and visual evoked potentials (VEPs). But few studies have been devoted to understanding the effects of nicotine alone. The purpose of this research was to examine the effects of oral administration of nicotine in human adults, who are non-smokers, on color vision, and visual cortical processing. Previous studies on adult smokers revealed that …
The Role Of Autosomal Dominant Retinitis Pigmentosa Rhodopsin Mutant Ter349glu In Rod Cell Biogenesis And Retinal Inflammation, Tj Hollingsworth
The Role Of Autosomal Dominant Retinitis Pigmentosa Rhodopsin Mutant Ter349glu In Rod Cell Biogenesis And Retinal Inflammation, Tj Hollingsworth
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Retinitis pigmentosa is one of the most common inherited blinding disorders, affecting 1 in 4000 individuals world-wide. Approximately 30% of retinitis pigmentosa cases are dominantly inherited and approximately 30% of these dominant mutations are found in rhodopsin. Most rhodopsin mutations result in misfolded protein aggregates and subsequent apoptosis while others have been shown to result in apoptosis associated with mislocalization, diminished/enhanced activity, or faulty protein-protein interactions. This work serves to test for mechanisms by which the naturally-occurring Ter349Glu rhodopsin mutation causes rod cell death. Ter349Glu rhodopsin was tested for the ability to bind the ligand 11-cis retinal, photoactivate, and activate …
The Effects Of Nicotine On The Human Adult Visual Pathway And Processing, Stefanie B. Varghese
The Effects Of Nicotine On The Human Adult Visual Pathway And Processing, Stefanie B. Varghese
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Nicotine, the primary addictive component found in tobacco/cigarettes, can bind to nicotinic acetylcholine receptors (nAChR), which are found throughout the central nervous system including the retina of the eye. Previous studies have shown nAChR expression in the retina of non-human and human (Hutchins & Hollyfield, 1985; Liu et al., 2009). By use of electrophysiologic measures, i.e. electroretinograms (ERGs), early reports indicated that nicotine and/or cigarette smoking affects vision and visual processing in different species (Jurklies, Kaelin-Lang, & Niemeyer, 1996; Jünemann & Damaske, 1968). Because previous human studies have used only cigarette smokers, there are questions about what role nicotine, itself, …
Adaptation To A Simulated Central Scotoma With Visual Search Tasks, Dave Walsh
Adaptation To A Simulated Central Scotoma With Visual Search Tasks, Dave Walsh
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This study characterized the perceptual and oculomotor adaptation to a simulated central scotoma in normally-sighted subjects and characterized the effects of two different scotoma profiles on the adaptation process. Twelve normally-sighted subjects, 6 for each type of scotoma profile, prac-ticed a search task (finding an "O" target among "C" distracters) for 11 blocks (162 trials per block). Search reaction time (RT) and eye movement data were collected. A head-mounted eye tracker was used to simulate two 10 deg circular central scotomas (CS), one with a sharp change from seeing to unseeing (S-CS) and the other with a gradual transition (G-CS). …
Schizophrenia And Vergence Eye Movements, Mark S. Bolding
Schizophrenia And Vergence Eye Movements, Mark S. Bolding
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Background: Compared to healthy controls (HC), patients with schizophrenia (SZ) have lower smooth pursuit gain and have been reported as having a higher prevalence of convergence insufficiency. To date, however, there have been no reports on vergence tracking gain in such patients. Therefore, we investigated both static and dynamic vergence behavior in healthy controls and patients with schizophrenia. Methods: Eye movements were recorded in multiple tasks including antisaccades, triangular waveform smooth pursuit at multiple frequencies, and triangular waveform vergence tracking of a real target at multiple frequencies. Eye position data were collected at 500 Hz using a binocular video eye …
Differential Expression Of Proteins In Keratoconus: Potential Role Of Human Antigen R (Hur) In Regulation Of Ss-Actin Gene, Roy Joseph
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DIFFERENTIAL EXPRESSION OF PROTEINS IN KERATOCONUS: POTENTIAL ROLE OF HUMAN ANTIGEN R (HuR) IN REGULATION OF ß-ACTIN ROY JOSEPH VISION SCIENCES ABSTRACT Keratoconus (KC) is a condition of unknown cause in which the cornea assumes a conical shape as a result of non-inflammatory thinning of the corneal stroma. The disease progresses at a variable speed with corneal thinning inducing irregular astigmatism, myopia, and corneal protrusion. Contact lenses, and ultimately keratoplasty, are often required to restore vision. Despite intensive investigations into the pathogenesis of KC, the exact cause of the disease is presently poorly understood. Keratoconus apparently arises due to number …
The Effect Of Acetylcholine Receptor Activation On The Response Properties Of Retinal Ganglion Cells, Ye Long
The Effect Of Acetylcholine Receptor Activation On The Response Properties Of Retinal Ganglion Cells, Ye Long
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Acetylcholine (ACh) is the first identified neurotransmitter and acts in areas including the peripheral nervous system (PNS) and the central nervous system (CNS). The effects of ACh are mediated by nicotinic and muscarinic acetylcholine receptors (AChRs), both of which are extensively distributed in CNS, including the retina. The expression and distribution of nicotinic AChRs (nAChRs) and muscarinic AChRs (mAChRs) have been studied with RT-PCR, western blot, and immunohistochemical techniques in the retinas of different species (Kaneda et al., 1995; Keyser et al., 2000; Yamada et al., 2003; Strang et al., 2005; Dmitrieva et al., 2007; Liu et al., 2009; Strang …
Electrophysiological Investigation Of Rabbit Retinal Ganglion Cells, Przemyslaw Nowak
Electrophysiological Investigation Of Rabbit Retinal Ganglion Cells, Przemyslaw Nowak
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The retina is the first stage of the visual system, responsible for transducing light into the neural signal and for subsequent processing of this signal before sending it to the higher visual centers in the brain. The output to the higher visual centers is mediated by retinal ganglion cells, which not only relay the signal, but also substantially contribute to its processing. Depending on what computations they perform, they are subdivided into different types. These cells have been extensively studied in various spices, one prominent example being the rabbit. In rabbits, one characteristic type comprises On-Off directionally selective retinal ganglion …
Post-Translational Modifications, Structure And Function Of Human Lens Crystallins, Chinwe Asomugha
Post-Translational Modifications, Structure And Function Of Human Lens Crystallins, Chinwe Asomugha
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Cataract is an opacification of the lens causing reduction in vision over time. It is one of the leading causes of vision loss among adults age 55 and older. The lens is a transparent structure that focuses incoming light onto the retina for visual perception. It has a high protein content, attributed mainly to water-soluble proteins known as crystallins. With age, crystallins undergo post-translational modifications (PTMs) that alter their structural and/or functional properties and, in turn, lead to cataract formation. The purpose of this research was to take a top-down approach in understanding changes in lens proteins with age, starting …
Behavior Of Midbrain Vergence Cells During Stepwise Transfers Of Gaze And Oblique Tracking In Depth, Leah Corthell
Behavior Of Midbrain Vergence Cells During Stepwise Transfers Of Gaze And Oblique Tracking In Depth, Leah Corthell
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A long standing debate regarding the neural organization of oculomotor control began in the late 1800's with Hering and von Helmholtz proposing two opposing ideologies. Von Helmholtz proposed a monocular structure of the oculomotor circuitry in which each eye receives separate motor commands. Hering offered his law of equal innervation, which states that all eye movements are the sum of binocular vergence and conjugate commands. As a test of Hering's binocular proposal, this project compared the behavior of midbrain vergence cells during: 1) saccade-free stepwise transfers of gaze in depth; 2) combined saccade-vergence eye movements; 3) pure vergence tracking, and …
Overexpression Of Garp2 Increases Phototransduction Gain., Shanta Sarfare
Overexpression Of Garp2 Increases Phototransduction Gain., Shanta Sarfare
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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 …
Response Dynamics Of Retinal Ganglion And Early Visual Cortical Cells To Simulated Optical Blur, Michael Lance Risner
Response Dynamics Of Retinal Ganglion And Early Visual Cortical Cells To Simulated Optical Blur, Michael Lance Risner
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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 …
Exploration Of The Crosslinks Between Saccadic And Vergence Eye Movement Pathways Using Motor And Visual Perturbations, Kevin Paul Schultz
Exploration Of The Crosslinks Between Saccadic And Vergence Eye Movement Pathways Using Motor And Visual Perturbations, Kevin Paul Schultz
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ANCOVA models to be non-orthogonal, we get similar results to the ANCOVA with
Modification Of Adenovirus Capsid Proteins For Gene Therapy Applications, Yizhe Tang
Modification Of Adenovirus Capsid Proteins For Gene Therapy Applications, Yizhe Tang
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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 …
Comparisons Between Behavioral And Electrophysiological Measures Of Visual Function In Rodent Models Of Retinal Degeneration, Glen R. Rubin
Comparisons Between Behavioral And Electrophysiological Measures Of Visual Function In Rodent Models Of Retinal Degeneration, Glen R. Rubin
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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 …
Patterns Of Differential Mrna And Protein Expression During Minus Lens Compensation And Recovery In Tree Shrew Sclera, Hong Gao
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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, …
Sustained Pupil Constriction Following Brief Light Exposure: Relation To Retinal Health, Laxmikanth Kankipati
Sustained Pupil Constriction Following Brief Light Exposure: Relation To Retinal Health, Laxmikanth Kankipati
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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 …
Effects Of Daily Versus 30-Day Continuous Contact Lens Wear On Tear Cytokine Levels, Lucy Ebunoluwa Kehinde
Effects Of Daily Versus 30-Day Continuous Contact Lens Wear On Tear Cytokine Levels, Lucy Ebunoluwa Kehinde
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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 …
Structural And Functional Properties Of Human Αa-Crystallin, Jose Mauro Chaves
Structural And Functional Properties Of Human Αa-Crystallin, Jose Mauro Chaves
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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 …
Punctal Occlusion Impact On Tear Film Immuno-Regulatory Proteins Measured By Cytometric Bead-Based Assay, Martin W. Lafrance
Punctal Occlusion Impact On Tear Film Immuno-Regulatory Proteins Measured By Cytometric Bead-Based Assay, Martin W. Lafrance
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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 …
The Role Of Melanopsin Containing Retinal Ganglion Cells In The Pupillary Responses Of Human And Non-Human Primates, David H. Mcdougal
The Role Of Melanopsin Containing Retinal Ganglion Cells In The Pupillary Responses Of Human And Non-Human Primates, David H. Mcdougal
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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 …
The Role Of Strychnine-Sensitive Nachrs In Rabbit Retinal Off Ganglion Cells, Jordan Michael Renna
The Role Of Strychnine-Sensitive Nachrs In Rabbit Retinal Off Ganglion Cells, Jordan Michael Renna
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that when heteroskedasticity is present, but ignored, there is significant evidence to suggest
Expression And Function Of Nicotinic Acetylcholine Receptors In Human Vascular Endothelial Cells, Ryan C. Splittgerber
Expression And Function Of Nicotinic Acetylcholine Receptors In Human Vascular Endothelial Cells, Ryan C. Splittgerber
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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 …
Retinal Pigment Epithelial Cells And The Insulin-Like Growth Factor System In Proliferative Vitreoretinopathy, Sudipto Mukherjee
Retinal Pigment Epithelial Cells And The Insulin-Like Growth Factor System In Proliferative Vitreoretinopathy, Sudipto Mukherjee
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The goal of this study was to determine the influence, if any, of the insulin-like growth factors (IGFs) on retinal pigment epithelial (RPE) cell tractional force generation and the contributions of vitreous insulin-like growth factor binding proteins (IGFBPs) towards control of IGF activity. Another objective was to evaluate RPE cells as a potential source of all six high-affinity IGFBPs and to determine if IGFBP biosynthesis is modulated in concert with phenotype changes and growth factor stimuli known to be present in disease. RPE generate tractional forces in response to IGF-I and -II with IGF-I being the more potent stimulus. Differential …
Effects Of Optical Blur On Visual Performance And Comfort Of Computer Users, Ferial M. Zeried
Effects Of Optical Blur On Visual Performance And Comfort Of Computer Users, Ferial M. Zeried
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Background. The study examined the effects of optical blur on the visual performance and comfort of computer workers. Since most workers have significant degrees of optical blur, the study may elucidate improved methodology for workplace comfort and function. Methods. Since young and old workers experience blur from different sources, the study incorporated two different designs. The study examined the correction of optical blur using a randomized, double-blind, placebo-controlled, crossover design. The primary outcomes of the study were visual comfort and productivity. In study one, subjects were required to be 19-35 yrs of age, have at least 0.50D uncorrected refractive error …