Optometry Commons^™

Addressing Artificial Intelligence Bias In Retinal Diagnostics, Philippe Burlina, Neil Joshi, William Paul, Katia D Pacheco, Neil M Bressler

Faculty, Staff and Students Publications

PURPOSE: This study evaluated generative methods to potentially mitigate artificial intelligence (AI) bias when diagnosing diabetic retinopathy (DR) resulting from training data imbalance or domain generalization, which occurs when deep learning systems (DLSs) face concepts at test/inference time they were not initially trained on.

METHODS: The public domain Kaggle EyePACS dataset (88,692 fundi and 44,346 individuals, originally diverse for ethnicity) was modified by adding clinician-annotated labels and constructing an artificial scenario of data imbalance and domain generalization by disallowing training (but not testing) exemplars for images of retinas with DR warranting referral (DR-referable) from darker-skin individuals, who presumably have greater …

Measuring Mitochondrial Respiration In Vivo: From Mouse To Human, Arthur Orchanian, Brennan Schilling, Bruce Berkowitz Phd

Medical Student Research Symposium

Introduction: The mitochondrial energy ecosystem can be non-invasively interrogated in photoreceptors by combing a clinical tool, optical coherence tomography (OCT), with a mitochondrial protonophore (2,4 dinitrophenol, DNP). It remains unclear if only supra-clinical doses of DNP will be useful for mouse studies or if lower but clinically relevant doses of DNP would facilitate translation from mice to humans.

Methods: The experiment was a paired longitudinal design that took place over 2 days. On day 1, C57BL/6J mice were overnight dark adapted, then light-adapted for 5 h before OCT examination before regaining consciousness; a similar procedure was followed on day 2 …

Presumed Diffuse Unilateral Subacute Neuroretinitis: A Review Supported By A Unique Case, Kirsti K. Ramirez Od, Joseph Pizzimenti Od, Jeannette Wong-Powell Od, Jeffrey Rabin Od

Optometric Clinical Practice

Diffuse unilateral subacute neuroretinitis (DUSN) is a rare, sight-threatening inflammatory condition caused by a nematode. It typically affects healthy children and young adults. Various nematodes have been implicated, including those that originate from dogs and raccoons. Late stage findings include optic nerve atrophy, retinal arterial attenuation, “retinitis pigmentosa-like” retinal pigmentary changes, and central and peripheral vision loss. We present a case study of long-standing DUSN. The combination of optical coherence tomography (OCT) and visual electrophysiology testing proved invaluable in establishing a presumptive diagnosis of this rare condition.

Prevalence Of Vitreomacular Traction In Patients 40 Years Of Age And Older, Julie Rodman

Student Theses, Dissertations and Capstones

Vitreomacular traction (VMT) is a condition characterized by an incomplete posterior vitreous detachment resulting in traction on the macula and decreased visual acuity. The process of vitreomacular traction can lead to a number of maculopathies including cystoid macular edema, epiretinal membranes, and macular holes. VMT is more common in patients over 40 years of age; however no population-based studies documenting the prevalence of VMT in this age group has been published. Purpose: The current study was undertaken to evaluate the prevalence of vitreomacular traction syndrome in the population aged above 40. Clinical examination does not adequately illustrate the extent of …

Elementary Photoreceptor Signaling In Human Vision, Kady Scarlett Bruce

All ETDs from UAB

To perceive a spot of light at photopic threshold, a minimum number of photons must be absorbed by cone photoreceptors. While many factors affecting psychophysical threshold have been studied, few have been examined at the single-cone level. Here we reveal how variation in synaptic weighting and signal integration among cones in the human retina occurs in vivo. Using an adaptive optics scanning laser ophthalmoscope (AOSLO) equipped with stimulation capabilities, we targeted cone-sized stimuli to single cones. Perceptual increment thresholds were measured from individual cones and cone pairs in 7 subjects using a Bayesian-based staircase method of threshold estimation. In 42 …

Efficient In Vitro Development Of Photoreceptors From Human Pluripotent Stem Cells, Joseph C. Reynolds

Dissertations, Masters Theses, Capstones, and Culminating Projects

Degeneration of the rod and cone photoreceptors in the human retina is among the most common causes of blindness. Replacing these damaged photoreceptors may help to restore vision. Repairing the damaged retina relies on the insertion of new, healthy cells. Embryonic stem (ES) cells and induced pluripotent stem (iPS) cells are two possible sources of photoreceptors to restore vision. Previous data shows that human ES cells and iPS cells can be differentiated into photoreceptors and transplanted into the eye to restore some vision. However, this process is inefficient, and costly. Here, we show a new method for inducing photoreceptor production …

Gene Expression Signatures In Tree Shrew Retina, Rpe, And Choroid During Experimental Myopia And Recovery, Li He

All ETDs from UAB

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 …

The Effects Of Nicotine On The Human Adult Visual Pathway And Processing, Stefanie B. Varghese

All ETDs from UAB

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, …

Localization Of Proteins Involved In Trafficking In Frog And Mouse Retina, Amie Marsh

All ETDs from UAB

The connecting cilium serves as the major route for protein transport from the inner to outer segment of photoreceptor cells. The hypothesis that all Congenital Stationary Night Blindness (CSNB) rhodopsin mutants travel properly to the rod outer segment in Xenopus laevis will be tested by preparing transgenic X. laevis expressing a rhodopsin mutation found in human CSNB, A295V. In addition, probing for the existence of potential proteins involved in regulating rhodopsin trafficking and monitoring their localization will contribute to a better understanding of the underlying pathway of intracellular photoreceptor trafficking.

Electrophysiological Investigation Of Rabbit Retinal Ganglion Cells, Przemyslaw Nowak

All ETDs from UAB

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 …

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 …

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 …

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 …

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 …