Browsing by Subject "Optic disk"

Now showing 1 - 3 of 3
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    Characterizing and quantifying the temporal relationship between structural and functional change in glaucoma
    (Public Library of Science, 2021-04-01) Chu, Fang-I; Racette, Lyne; Ophthalmology, School of Medicine
    Purpose: To characterize and quantify the temporal relationship between structural and functional change in glaucoma. Methods: 120 eyes of 120 patients with ocular hypertension or primary open-angle glaucoma were selected from the Diagnostic Innovations in Glaucoma Study or the African Descent and Glaucoma Evaluation Study. Patients had 11 visits, separated by at least 3 months over 5 to 10 years. Each visit had rim area (RA) and mean sensitivity (MS) measurements taken within a 30-day period. The structure-function (SF) relationship was summarized using conventional and modified cross-correlation functions (CCFs), which identified the strongest absolute and positive correlation, respectively. Patients were categorized in one of the following three groups: RA and MS evolved simultaneously (lag = 0), RA preceded MS (lag<0), and MS preceded RA (lag>0). Lagging regression analysis was used to examine the variations of the SF relationship within groups. Results: The number of participants, mean visit lag, and mean correlation (standard deviation) were, for the conventional and modified CCFs, respectively: lag = 0 [16, 0, 0.53 (0.10) and 16, 0, 0.46 (0.11)]; lag<0 [50, -2.94, 0.51 (0.11) and 55, -3.45, 0.44 (0.12)], and lag>0 [54, 3.35, 0.53 (0.13) and 49, 3.78, 0.45 (0.12)]. A significant difference of the visit lag relation within groups was identified using lagging regression analysis (p<0.0001). Conclusions: The strongest relationship between structure and function was obtained at different visit lags in different patients. This finding also suggests that the SF relationship should be addressed at the subject level when using both measurements jointly to model glaucoma progression.
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    Ocular Hemodynamics and Glaucoma: The Role of Mathematical Modeling
    (Sage, 2013) Harris, Alon; Guidoboni, Giovanna; Arciero, Julia C.; Amireskandari, Annahita; Tobe, Leslie A.; Siesky, Brent A.; Ophthalmology, School of Medicine
    Purpose: To discuss the role of mathematical modeling in studying ocular hemodynamics, with a focus on glaucoma. Methods: We reviewed recent literature on glaucoma, ocular blood flow, autoregulation, the optic nerve head, and the use of mathematical modeling in ocular circulation. Results: Many studies suggest that alterations in ocular hemodynamics play a significant role in the development, progression, and incidence of glaucoma. Although there is currently a limited number of studies involving mathematical modeling of ocular blood flow, regulation, and diseases (such as glaucoma), preliminary modeling work shows the potential of mathematical models to elucidate the mechanisms that contribute most significantly to glaucoma progression. Conclusion: Mathematical modeling is a useful tool when used synergistically with clinical and laboratory data in the study of ocular blood flow and glaucoma. The development of models to investigate the relationship between ocular hemodynamic alterations and glaucoma progression will provide a unique and useful method for studying the pathophysiology of glaucoma.
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    Regional Vessel Density Reduction in the Macula and Optic Nerve Head of Patients With Pre-Perimetric Primary Open Angle Glaucoma
    (Wolters Kluwer, 2023) Verticchio Vercellin, Alice; Siesky, Brent; Antman, Gal; Oddone, Francesco; Chang, Michael; Eckert, George; Arciero, Julia; Kellner, Rebecca L.; Fry, Brendan; Coleman-Belin, Janet; Carnevale, Carmela; Harris, Alon; Biostatistics and Health Data Science, Richard M. Fairbanks School of Public Health
    Purpose: To investigate optic nerve head (ONH) and macular vessel densities (VD) and structural parameters assessed by optical coherence tomography angiography (OCTA) in pre-perimetric open-angle glaucoma (ppOAG) patients and healthy controls. Methods: 113 healthy and 79 ppOAG patients underwent global and regional (hemispheric/quadrants) assessments of retinal, ONH, and macular vascularity and structure, including ONH parameters, retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) thickness. Comparisons between outcomes in ppOAG and controls were adjusted for age, sex, race, BMI, diabetes, and hypertension, with p<0.05 considered statistically significant. Results: In ppOAG compared to healthy controls: RNFL thicknesses was statistically significantly lower for all hemispheres, quadrants and sectors (p<0.001–0.041); whole image peripapillary all and small blood vessels VD were statistically significantly lower for all the quadrants (p<0.001–0.002), except for the peripapillary small vessels in the temporal quadrant (ppOAG: 49.66 (8.40), healthy: 53.45 (4.04); p=0.843); GCC and inner and full macular thicknesses in the parafoveal and perifoveal regions were significantly lower in all the quadrants (p=0.000-p=0.033); several macular VD were significantly lower (p=0.006–0.034), with the exceptions of macular center, parafoveal superior and inferior quadrant, and perifoveal superior quadrant (p>0.05). Conclusions: In ppOAG patients, VD biomarkers in both the macula and ONH, alongside RNFL, GCC, and macular thickness were significantly reduced prior to detectable VF loss with regional specificity. The most significant VD reduction detected was in the peripheric (perifovea) regions. Macular and ONH decrease in VD may serve as early biomarker of glaucomatous disease.