Browsing by Subject "optic nerve"

Now showing 1 - 4 of 4
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    Does Knowledge of the Causes of Glaucoma Impact Adherence?
    (Office of the Vice Chancellor for Research, 2016-04-08) Diallo, Kadé; Bigatti, Silvia M.; Sutton, Bradley; Torbit, Julie; Racette, Lyne
    Purpose: Glaucoma is informally known as loss of sight due to the deterioration or damage to the optic nerve; some scientists claim to have identified the genes related to these causes. The most prevalent risk factor includes those of African descendant. We tested the hypothesis that the adherence level is higher in patients with more knowledge of their condition than those with none. Methods: A dataset of the first visit from a clinical diagnosis of open-angle glaucoma was retrieved, in which all the patients administered once-daily prostaglandin analog eye drops themselves. Participants were on average 60.38±9.93yrs of age and identified as African descendants; of the 29 patients, 16 self-identified as male and the rest female. Participants were specifically asked to “Please list in rank-order the three most important factors that you believe caused your illness”. We grouped the results into three different conditions: (1) those with at least on “true” (current factors that are widely accepted scientifically) risk factors vs those with none, (2) those who included race as a risk factor vs those who did not, and (3) those who listed any risk factors vs those with none. We compared the adherence within each condition using two-tailed t-test to calculate the “level of significance”. Results: Our results did not agree with our hypothesis. The values returned were: (1) 0.1244, (2) 0.3744, and (3) 0.2516. Because all three results were ≥ 0.05, our data displayed that there were no relationship between the groups. It meant that our outcomes were most likely a consequence of chance with no significance. Conclusions: Though our results were not consistent with our hypothesis, we were still able to come to a different deduction: whether or not individuals are educated on the causes of their conditions, their adherence will only improve if they decide it so.
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    Reductions in retrobulbar and retinal capillary blood flow strongly correlate with changes in optic nerve head and retinal morphology over four years in open-angle glaucoma patients of African descent compared to patients of European descent
    (Wolters Kluwer, 2016-09) Siesky, Brent; Harris, Alon; Carr, Joseph; Vercellin, Alice Verticchio; Hussain, Rehan; Hembree, Priyanka Parekh; Wentz, Scott; Isaacs, Michael; Eckert, George; Moore, Nicholas A.; Ophthalmology, School of Medicine
    Purpose To investigate the relationship of changes in ocular blood flow with optic nerve head and retinal morphology in open-angle glaucoma patients of African versus European descent over four years. Materials and Methods In this study, 112 patients with open-angle glaucoma were examined at baseline, 79 (59 European descent, 20 African descent) of which were followed for four years. Retinal capillary blood flow was assessed with Heidelberg retinal flowmetry. Retrobulbar blood flow was measured by color Doppler imaging. Retinal structural changes were examined with optical coherence tomography and Heidelberg retinal tomography-III. Mixed-model analysis of covariance was used to test for the significance of change from baseline to four-year follow-up, and Pearson correlation coefficients were calculated to evaluate linear associations. Results In open-angle glaucoma patients of African descent, structural changes of the optic nerve head demonstrated a strong association with the end diastolic velocities and resistive indices of the short posterior ciliary arteries over four years. In addition, there was a significantly larger increase in the avascular area of the inferior retina in patients of African descent, and this reduction in retinal capillaries strongly correlated with a reduction in macular thickness. Conclusion Reductions in retinal capillary and retrobulbar blood flow strongly correlated with changes in the optic nerve head and macular thickness over four years in open-angle glaucoma patients of African descent compared to European descent. This data suggests that ocular vascular health may be a more influential contributing factor in the pathophysiology of open-angle glaucoma in patients of African descent compared to European descent.
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    The Effects of Hydrocephalus on the Retina and the Optic Nerve
    (2023-12) Loftin, Michelle; Belecky-Adams, Teri; Blazer-Yost, Bonnie; Jantzie, Lauren
    Papilledema is the swelling of the optic disc resulting from increased cranial pressure (ICP). A diagnosis of papilledema is important to not only treat pathologies of the eye, but it also can be an important indicator of underlying brain pathology since the subarachnoid space surrounding the optic nerve is contiguous with the brain. Therefore, the increased cranial pressure from brain pathology can be transmitted to the eye. Thus, it is important to have further understanding of the mechanism of papilledema and the anatomical and cellular changes that occur with sustained ICP. To study papilledema, a reproducible post hemorrhagic hydrocephalic (PHH) rat model was used to study the changes of the retina, optic disc, and optic nerve when exposed to high levels of ICP. Multiple retinal changes were noted in the PHH rats including decreased retinal thickness in the peripheral retina in female rats and increased retinal thickness close to the optic disc in male rats. PHH caused a decrease in ganglion cell layer thickness in the peripheral retina. In addition, vascular changes were noted with the PHH rats having an increased occurrence of enlarged retinal vasculature. In addition, the PHH rats had an increased optic disc width from analyzed retinal sections and increased optic disc diameter on optical coherence tomography (OCT). Also, PHH caused a decrease in retinal ganglion cells (RGC). These experiments confirm that PHH model in rats can produce retinal and optic disc phenotypes that are similar to those found in human pathology. Therefore, future studies are indicated utilizing the PHH rat model to provide further understanding of the mechanism of papilledema progression and to allow for the study of possible therapeutics.
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    Visualization of human optic nerve by diffusion tensor mapping and degree of neuropathy
    (PLOS, 2022-12-12) Łabieniec, Łukasz; Lisowski, Łukasz; Petrache, Horia I.; Hładuński, Marcin; Konopińska, Joanna; Kochanowicz, Jan; Szymański , Krzysztof R.; Physics, School of Science
    Diffusion-weighted magnetic resonance imaging of the human optic nerve and tract is technically difficult because of its small size, the inherent strong signal generated by the surrounding fat and the cerebrospinal fluid, and due to eddy current-induced distortions and subject movement artifacts. The effects of the bone canal through which the optic nerve passes, and the proximity of blood vessels, muscles and tendons are generally unknown. Also, the limited technical capabilities of the scanners and the minimization of acquisition times result in poor quality diffusion-weighted images. It is challenging for current tractography methods to accurately track optic pathway fibers that correspond to known anatomy. Despite these technical limitations and low image resolution, here we show how to visualize the optic nerve and tract and quantify nerve atrophy. Our visualization method based on the analysis of the diffusion tensor shows marked differences between a healthy male subject and a male subject with progressive optic nerve neuropathy. These differences coincide with diffusion scalar metrics and are not visible on standard morphological images. A quantification of the degree of optic nerve atrophy in a systematic way is provided and it is tested on 9 subjects from the Human Connectome Project.