Browsing by Subject "Ocular blood flow"

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    Ocular blood flow as a clinical observation: Value, limitations and data analysis
    (Elsevier, 2020) Harris, Alon; Guidoboni, Giovanna; Siesky, Brent; Mathew, Sunu; Verticchio Vercellin, Alice C.; Rowe, Lucas; Arciero, Julia; Radiology and Imaging Sciences, School of Medicine
    Alterations in ocular blood flow have been identified as important risk factors for the onset and progression of numerous diseases of the eye. In particular, several population-based and longitudinal-based studies have provided compelling evidence of hemodynamic biomarkers as independent risk factors for ocular disease throughout several different geographic regions. Despite this evidence, the relative contribution of blood flow to ocular physiology and pathology in synergy with other risk factors and comorbidities (e.g., age, gender, race, diabetes and hypertension) remains uncertain. There is currently no gold standard for assessing all relevant vascular beds in the eye, and the heterogeneous vascular biomarkers derived from multiple ocular imaging technologies are non-interchangeable and difficult to interpret as a whole. As a result of these disease complexities and imaging limitations, standard statistical methods often yield inconsistent results across studies and are unable to quantify or explain a patient's overall risk for ocular disease. Combining mathematical modeling with artificial intelligence holds great promise for advancing data analysis in ophthalmology and enabling individualized risk assessment from diverse, multi-input clinical and demographic biomarkers. Mechanism-driven mathematical modeling makes virtual laboratories available to investigate pathogenic mechanisms, advance diagnostic ability and improve disease management. Artificial intelligence provides a novel method for utilizing a vast amount of data from a wide range of patient types to diagnose and monitor ocular disease. This article reviews the state of the art and major unanswered questions related to ocular vascular anatomy and physiology, ocular imaging techniques, clinical findings in glaucoma and other eye diseases, and mechanistic modeling predictions, while laying a path for integrating clinical observations with mathematical models and artificial intelligence. Viable alternatives for integrated data analysis are proposed that aim to overcome the limitations of standard statistical approaches and enable individually tailored precision medicine in ophthalmology.
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    Should Men and Women be Managed Differently in Glaucoma?
    (Springer, 2012) Abrams Tobe, Leslie; Harris, Alon; Trinidad, Jake; Chandrasekhar, Kaarthik; Cantor, Adam; Abrams, John; Amireskandari, Annahita; Siesky, Brent; Ophthalmology, School of Medicine
    Introduction: To assess differences in associations of ocular perfusion pressure (OPP) as well as retinal and retrobulbar blood flow between men and women with primary open angle glaucoma (OAG). Methods: A total of 116 patients with OAG (age 66.9 ± 10.9 years, 70 females) participating in the Indianapolis Glaucoma Progression Study were assessed for OPP, retinal microcirculation, and retrobulbar blood flow. Confocal scanning laser Doppler flowmetry measured peripapillary retinal capillary blood flow. Color Doppler imaging measured peak systolic (PSV) and diastolic blood flow velocities and vascular resistance in the ophthalmic (OA), central retinal (CRA), and nasal and temporal short posterior ciliary arteries (N/T PCA). Bivariate Spearman correlation and multivariate linear regression analyses were performed. Results: In female patients with OAG, inferior retinal capillary flow was associated with OPP (r = 0.246, P = 0.044). In men, superior and inferior sector retinal blood flow was associated with OPP (r = -0.402, P = 0.006 and r = -0.357, P = 0.016, respectively). There was no statistically significant association between OPP and retrobulbar blood vessel flow velocities in male patients with OAG but there was an association between OA and TPCA PSV and OPP in female patients with OAG (r = 0.290, P = 0.015 and r = 0.357, P = 0.002, respectively). In female patients with OAG, multivariate regression showed no statistically significant effect of any variable on the superior retinal capillary blood flow, with CRA PSV as a sole predictor to the inferior retinal sector (partial rho = 0.302, P = 0.015) and in male patients with OAG, superior sector retinal capillary blood flow was independently associated with intraocular pressure (partial rho = -0.371, P = 0.016) and OPP (partial rho = -0.456, P = 0.002) with a trend of association with OPP in the inferior retina (partial rho = -0.301, P = 0.053). Conclusions: There was a positive linear association between retinal microcirculation and OPP in females and a negative association in males. Male and female patients with OAG may differ in their vascular autoregulation in response to changes in OPP.