Browsing by Author "Verticchio, Alice"

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    Artificial Intelligence to Aid Glaucoma Diagnosis and Monitoring: State of the Art and New Directions
    (MDPI, 2022) Nunez, Roberto; Harris, Alon; Ibrahim, Omar; Keller, James; Wikle, Christopher K.; Robinson, Erin; Zukerman, Ryan; Siesky, Brent; Verticchio, Alice; Rowe, Lucas; Guidoboni, Giovanna; Ophthalmology, School of Medicine
    Recent developments in the use of artificial intelligence in the diagnosis and monitoring of glaucoma are discussed. To set the context and fix terminology, a brief historic overview of artificial intelligence is provided, along with some fundamentals of statistical modeling. Next, recent applications of artificial intelligence techniques in glaucoma diagnosis and the monitoring of glaucoma progression are reviewed, including the classification of visual field images and the detection of glaucomatous change in retinal nerve fiber layer thickness. Current challenges in the direct application of artificial intelligence to further our understating of this disease are also outlined. The article also discusses how the combined use of mathematical modeling and artificial intelligence may help to address these challenges, along with stronger communication between data scientists and clinicians.
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    Metabolic blood flow regulation in a hybrid model of the human retinal microcirculation
    (Elsevier, 2023) Albright, Amanda; Fry, Brendan C.; Verticchio, Alice; Siesky, Brent; Harris, Alon; Arciero, Julia; Mathematical Sciences, School of Science
    The retinal vascular network supplies perfusion to vital visual structures, including retinal ganglion cells responsible for vision. Impairments in retinal blood flow and oxygenation are involved in the progression of many ocular diseases, including glaucoma. In this study, an established theoretical hybrid model of a retinal microvascular network is extended to include the effects of local blood flow regulation on oxygenation. A heterogeneous representation of the arterioles based on confocal microscopy images is combined with a compartmental description of the downstream capillaries and venules. A Green’s function method is used to simulate oxygen transport in the arterioles, and a Krogh cylinder model is applied to the capillary and venular compartments. Acute blood flow regulation is simulated in response to changes in pressure, shear stress, and metabolism. Model results predict that both increased intraocular pressure and impairment of blood flow regulation can cause decreased tissue oxygenation, indicating that both mechanisms represent factors that could lead to impaired oxygenation characteristic of ocular disease. Results also indicate that the metabolic response mechanism reduces the fraction of poorly oxygenated tissue but that the pressure- and shear stress-dependent response mechanisms may hinder the vascular response to changes in oxygenation. Importantly, the heterogeneity of the vascular network demonstrates that traditionally reported average values of tissue oxygen levels hide significant localized defects in tissue oxygenation that may be involved in disease processes, including glaucoma. Ultimately, the model framework presented in this study will facilitate future comparisons to sectorial-specific clinical data to better assess the role of impaired blood flow regulation in ocular disease.
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    Using a Theoretical Model to Assess the Impact of Vascular Risk Factors on Autoregulation in the Retina
    (Association for Research in Vision and Ophthalmology, 2025) Fry, Brendan C.; Arciero, Julia C.; Gyurek, Croix; Albright, Amanda; Siesky, Brent; Verticchio, Alice; Harris, Alon; Mathematical Sciences, School of Science
    Purpose: Vascular impairments, including reduced capillary density (CD), impaired autoregulation capacity (Reg), and elevated intraocular pressure (IOP), have been identified as significant contributors to glaucomatous disease. This study implemented a theoretical model to quantify the impact of these impairments on retinal blood flow and oxygenation as intraluminal pressure (Pa) is varied. Methods: A theoretical model of the retinal vasculature was used to simulate reductions in CD by 10% (early glaucoma) and 30% to 50% (advanced glaucoma), a range in autoregulation capacity from 0% (totally impaired) to 100% (totally functional), and normal (15 mm Hg) and elevated (25 mm Hg) levels of IOP. Results: Under baseline conditions of CD = 500 mm-2, Reg = 100%, and IOP = 15 mm Hg, an autoregulation plateau was predicted for Pa = 28 to 44 mm Hg. Decreased CD, impaired flow regulation mechanisms, and increased IOP all cause a loss of the autoregulation plateau and a corresponding decrease in tissue oxygenation in this pressure range. Although the detrimental effects of small decreases in CD or elevations in IOP are mostly offset by functional flow regulation, larger changes and/or combinations of vascular impairments lead to a significant drop in retinal oxygenation. Conclusions: Model predictions indicate that isolated or combined vascular impairments in CD, flow regulation, and IOP contribute to poor retinal tissue oxygenation, which could lead to vision loss in advanced glaucoma patients. This study motivates early identification of vascular changes to prevent a substantially worse effect of these factors on retinal oxygenation during the progression of glaucoma.