Papers by Abdelmonem Afifi
American Journal of Cardiology, Jun 1, 1974
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Journal of Glaucoma, Feb 18, 2022
Précis: We describe a method that provides rapid visualization of glaucomatous change in a 2-dime... more Précis: We describe a method that provides rapid visualization of glaucomatous change in a 2-dimensional (2D) structural and functional (S/F) space. Purpose: To describe a method to visualize glaucomatous change in a 2D S/F space. Design: This was a retrospective longitudinal observational study. Subjects: Group I included 64 normal and 64 glaucomatous eyes used to develop the structural score. Group II included 957 glaucomatous eyes used to plot the structural-functional progression vectors. Methods: Subjects were arranged in 2 groups. Group I was a cross-sectional group used to develop a structural score which were applied to longitudinal measurements of patients in group II for vectoral analysis. Visual field index was used as a functional score. Vectors were created for each eye to define structural (x) and functional (y) progression. The structural and functional components were calculated with linear models of optical coherence tomography scores and visual field index. The resultant vector and its confidence interval were plotted in 2D S/F space. Main Outcome Measures: Combined structural-functional glaucomatous progression. Results: Group I included 64 normal and 64 glaucomatous eyes. We calculated 957 vectors (957 eyes of 582 OAG patients) in group II. The mean (±SD) follow-up period was 6.9 (±1.5) years and mean baseline mean deviation (MD) was −4.3 (±5.4). Preperimetric, mild, moderate, and severe groups included 159, 288, 299, and 211 eyes, respectively. Mean baseline MDs in these groups were 0.8, −1.0, −3.7, and −11.2 dB, and mean vector slopes were 0.88, 1.00, 1.98, and 2.69. Conclusion: We present a method that presents glaucoma progression in a 2D S/F space. This approach integrates a large amount of longitudinal numerical data and provides the clinician with a rapid and intuitive summary of the patient’s glaucoma trajectory.
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Chapman and Hall/CRC eBooks, Oct 16, 2019
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Investigative Ophthalmology & Visual Science, Jun 16, 2013
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Journal of Trauma-injury Infection and Critical Care, Aug 1, 1972
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Investigative Ophthalmology & Visual Science, Jun 16, 2013
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Quantitative assessment of the severity of illness and prognosis of critically ill patients provi... more Quantitative assessment of the severity of illness and prognosis of critically ill patients provides a basis for objective evaluation of selective aspects of patient care. In studies on patients with acute myocardial infarction and shock, linear combinations of cardiac index and lactate were most reliable for estimating severity of illness and prognosis (1). When patients with shock due to drug overdose were analyzed, two different variables emerged as the most reliable indicators, systolic pressure and arterial pH (2). The present study was undertaken to identify the most useful hemodynamic, respiratory and metabolic variables for assessing the severity of illness in patients with shock due to gram-negative bacterial infection. Prognostic indices based on combinations of these variables were derived. The effect of the time of the measurements also was evaluated to determine its influence on the reliability of the prognosis.
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Investigative Ophthalmology & Visual Science, Jul 22, 2019
PURPOSE To identify predictive factors for visual field (VF) fluctuation in glaucoma patients. DE... more PURPOSE To identify predictive factors for visual field (VF) fluctuation in glaucoma patients. DESIGN Retrospective cohort study. PARTICIPANTS A total of 1392 eyes (816 patients) with 6 or more VFs and 3 years or more of follow-up. METHODS For each eye, the VF mean deviation (MD) and the pointwise sensitivities were regressed against time to model the series trend, and the root mean square error (RMSE) was estimated as a measure of variability. Potential predictors were selected with least absolute shrinkage and selection operator regression and included eye laterality, ethnicity, glaucoma type, intraocular pressure (IOP) fluctuation, baseline best corrected-visual acuity, intervening cataract or glaucoma surgery, length of follow-up, frequency of testing, baseline MD, rates of VF progression, and median false positive (FP) and false negative (FN) responses. MAIN OUTCOME MEASURES Predictors of global and pointwise VF long-term fluctuation. RESULTS In the global model, left eye (0.063 dB; P = 0.022), Asian descent (0.265 dB; P = 0.006), larger IOP fluctuation (0.051 dB; P < 0.001), intervening cataract surgery (0.090 dB; P = 0.023), longer follow-up (0.130 dB; P < 0.001), worse baseline MD (-0.145 dB; P < 0.001), faster VF decay rate (-0.090 dB; P < 0.001), and higher FP rate (0.145 dB; P < 0.001) and FN rate (0.220 dB; P < 0.001) were predictors of VF fluctuation. In the pointwise model, larger IOP fluctuation (0.039 dB; P = 0.022), longer follow-up (0.340 dB; P < 0.001), higher VF frequency (0.238 dB; P = 0.002), intervening glaucoma surgery (0.190 dB; P = 0.01), worse baseline MD (-0.535 dB; P < 0.001), faster VF decay rate (-0.340 dB; P < 0.001), and higher FP rate (0.255 dB; P < 0.001) and FN rate (0.395 dB; P < 0.001) were associated with increased fluctuation. The multivariable model explained 57% and 28% of the pointwise and global variances, respectively. CONCLUSIONS This study identified novel predictors of VF fluctuation, and explains nearly 60% of the pointwise variance. In the presence of factors predictive of high fluctuation, increased frequency of testing and better analytics will help to identify VF progression more accurately.
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Ophthalmology Glaucoma, Nov 1, 2020
PURPOSE To present a method that allows visualization of functional and structural change in 2-di... more PURPOSE To present a method that allows visualization of functional and structural change in 2-dimensional space. DESIGN Retrospective, longitudinal, observational study. PARTICIPANTS Patients from the Stein Eye Institute, UCLA from 1993 through 2017. METHODS Patients were arranged into 2 cohorts. Cohort 1 was used to create a structural score for the horizontal axis of the structural-functional (S-F) 2-dimensional space. The visual field (VF) index was used for the vertical axis as the functional score. Cohort 2 was used to apply those scores for analysis of S-F progression with a combined vector. The first cohort included eyes with mild glaucoma (abnormal glaucoma hemifield test results, pattern standard deviation <0.05 on 2 examinations, or mean deviation [MD] >-5 dB) and normal control participants. The second cohort included all stages of open-angle glaucoma with ≥5 OCT retinal nerve fiber layer scans, ≥5 reliable visual field (VF) results, and follow-up of ≥4 years. MAIN OUTCOME MEASURES Vectors were created for each eye to represent the trajectory of glaucoma progression over time. Each vector was defined by structural (x-axis) and functional (y-axis) components. The structural component was calculated with a linear model of Heidelberg Retina Tomograph (Heidelberg Engineering, Heidelberg, Germany) scores over time. The functional component was calculated with a linear model of VF measurements over time. The resultant vector and its confidence interval were plotted in 2-dimensional S-F space. Eyes were divided into severity stages based on baseline MD. A mean vector was calculated for each severity stage. RESULTS We obtained 290 vectors from 290 eyes of 196 patients. The mean ± standard deviation follow-up period was 14.6±3.1 years. Average age was 58.6±8.8 years. Preperimetric, mild, moderate, and severe categories included 41, 89, 97, and 63 eyes, respectively. Mean baseline MDs were 0.8 dB, -0.95 dB, -3.57 dB, and -11.51 dB, respectively, and mean vector slopes for each severity categories were 0.79, 0.95, 1.95, and 2.08, respectively. Cook's distance removed 131 (7.1%) and 137 (7.4%) outliers from the structure and function regressions, respectively. CONCLUSIONS We report a method to visualize the trajectory of a patient's glaucoma progression in a 2-dimensional S-F space. The slope of the trajectory of glaucoma progression is a function of the severity of the disease.
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Investigative Ophthalmology & Visual Science, Apr 22, 2011
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JAMA Ophthalmology, Aug 1, 2015
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medRxiv (Cold Spring Harbor Laboratory), Mar 12, 2021
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American Journal of Ophthalmology, Mar 1, 2010
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Papers by Abdelmonem Afifi