Browsing by Author "Chu, Fang-I"

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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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    Impact of self-efficacy and demographic factors on adherence to treatment in glaucoma patients of African descent
    (Investigative Ophthalmology and Visual Science Journal, 2017) Alkhairy, Sameerah; Chu, Fang-I; Ramezani, Koosha; McIntyre, Elizabeth; Sutton, Bradley; Torbit, Julie; Bigatti, Silvia
    Purpose : To determine whether self-efficacy and demographic factors influence adherence to the medical treatment of glaucoma in patients of African descent. Methods : 37 patients with a clinical diagnosis of primary open-angle glaucoma were included in this cross-sectional study. All patients were of African descent, used self-administered once-daily prostaglandin analog eye drops. Adherence was measured in 34 patients during a one-month period (mean 28.8 days) using Medical Event Monitoring System (MEMS) caps. The caps of these bottles electronically record the date and time at which the bottle is opened. All patients completed the four following questionnaires: Q1) glaucoma medication self-efficacy scale, Q2) eye drop technique self-efficacy scale, Q3) reported adherence to medication questionnaire and Q4) brief illness perception questionnaire. All answers were treated as ordinal variable and total scores for each questionnaire were computed. The impact of these four self-efficacy scores on adherence was assessed using linear regression models. We also determined how demographic factors (age, gender, education, marital status, employment status, and income) modulated this relationship. Finally, we assessed the influence of these demographic factors on the self-efficacy scores. Results : The mean age was 60.89±9.81 and 45.95% of patients were female. Eye drop technique self-efficacy (Q2) had a borderline negative impact on adherence (slope=−3.64, p=0.05), such that higher self-efficacy resulted in lower adherence. This result was minimized by being older (p=0.03) or divorced/separated (p=0.04) compared to being single/widowed (increase in the impact of self-efficacy on adherence). Similarly, the relationship between glaucoma medication self-efficacy (Q1) and adherence was negatively modulated by being married/partnered (p=0.04) compared to being single/widowed (decrease in the impact of self-efficacy on adherence). A negative impact of being male was also observed on Q1 (score=−6.28, p=0.05). Conclusions : Overall, patients who were confident in how to administer their eye drops had worse adherence, but this effect was minimized in older and divorced individuals. Overall, being male had a negative impact on self-efficacy as it relates to glaucoma medication. These results suggest that the relationship between self-efficacy and adherence is complex and affected by several factors. This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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    Restructuring of the Gut Microbiome by Intermittent Fasting Prevents Retinopathy and Prolongs Survival in db/db Mice
    (American Diabetes Association, 2018-09) Beli, Eleni; Yan, Yuanqing; Moldovan, Leni; Vieira, Cristiano P.; Gao, Ruli; Duan, Yaqian; Prasad, Ram; Bhatwadekar, Ashay; White, Fletcher A.; Townsend, Steven D.; Chan, Luisa; Ryan, Caitlin N.; Morton, Daniel; Moldovan, Emil G.; Chu, Fang-I; Oudit, Gavin Y.; Derendorf, Hartmut; Adorini, Luciano; Wang, Xiaoxin X.; Evans-Molina, Carmella; Mirmira, Raghavendra G.; Boulton, Michael E.; Yoder, Mervin C.; Li, Qiuhong; Levi, Moshe; Busik, Julia V.; Grant, Maria B.; Pediatrics, School of Medicine
    Intermittent fasting (IF) protects against the development of metabolic diseases and cancer, but whether it can prevent diabetic microvascular complications is not known. In db/db mice, we examined the impact of long-term IF on diabetic retinopathy (DR). Despite no change in glycated hemoglobin, db/db mice on the IF regimen displayed significantly longer survival and a reduction in DR end points, including acellular capillaries and leukocyte infiltration. We hypothesized that IF-mediated changes in the gut microbiota would produce beneficial metabolites and prevent the development of DR. Microbiome analysis revealed increased levels of Firmicutes and decreased Bacteroidetes and Verrucomicrobia. Compared with db/db mice on ad libitum feeding, changes in the microbiome of the db/db mice on IF were associated with increases in gut mucin, goblet cell number, villi length, and reductions in plasma peptidoglycan. Consistent with the known modulatory effects of Firmicutes on bile acid (BA) metabolism, measurement of BAs demonstrated a significant increase of tauroursodeoxycholate (TUDCA), a neuroprotective BA, in db/db on IF but not in db/db on AL feeding. TGR5, the TUDCA receptor, was found in the retinal primary ganglion cells. Expression of TGR5 did not change with IF or diabetes. However, IF reduced retinal TNF-α mRNA, which is a downstream target of TGR5 activation. Pharmacological activation of TGR5 using INT-767 prevented DR in a second diabetic mouse model. These findings support the concept that IF prevents DR by restructuring the microbiota toward species producing TUDCA and subsequent retinal protection by TGR5 activation.
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    Structure-­Function Associations in Healthy and Glaucoma Eyes
    (Office of the Vice Chancellor for Research, 2016-04-08) Chu, Fang-I; Marin‐Franch, Iván; Ramezani, Koosha; Racette, Lyne
    Purpose: To determine whether differences exist in the structure--‐function associations between healthy and glaucoma eyes. Methods: Structure--‐function associations were assessed in three different datasets. First, in the Diagnostic Innovation and Glaucoma Study and African Descent and Glaucoma Evaluation Study, associations between rim area (RA) (Heidelberg Retina Tomography II) and both mean sensitivity (MS) and mean deviation (MD) from conventional automated perimetry (CAP) were assessed in 698 healthy subjects and 1036 glaucoma patients. Associations between retinal nerve fiber layer thickness (RNFLT) from the Spectralis optical coherence tomography (OCT) (Heidelberg Engineering) and MS or MD from CAP were assessed in 198 healthy subjects and 634 glaucoma patients. Second, in the dataset used in Swanson et al (2014), the association between RNFLT from the Stratus OCT (Heidelberg Engineering) and MD from CAP, measures from contrast sensitivity perimetry (CSP--‐2), and from frequency--‐doubling perimetry (FDP) in the superior temporal (ST) and inferior temporal (IT) optic disc sectors were assessed in 62 healthy subjects and 51 glaucoma patients. Third, in a dataset obtained from Iowa University, association between RNFLT and relative field sensitivity was assessed in 79 healthy subjects. All associations were assessed with the generalized estimating equation (GEE) procedure, linear mixed effect model (LMM), and the Pearson, Spearman and Kendall correlations. Age was included to adjust for its confounding effect in all GEE and LMM models. Results: For healthy eyes, no significant structure--‐function association was found using GEE, Pearson, Spearman and Kendall correlations. With LMM, a significant association was found between RNFLT and both MS and MD. For glaucoma eyes, significant associations were found with all methods. Conclusion: Significant structure--‐function associations were identified in glaucoma eyes but not in healthy ones. This suggests that the structure--‐function associations should be considered separately in healthy and glaucoma eyes because of the different nature of the associations. Eugene and Marilyn Glick Eye Institute, Indiana University, Indianapolis IN, US. Departamento de Óptica. Facultad de Física. Universitat de València, Burjassot, Valencia, Spain. Eugene and Marilyn Glick Eye Institute, Indiana University, Indianapolis IN, US. Eugene and Marilyn Glick Eye Institute, Indiana University, Indianapolis IN, US. Acknowledgement: This project was supported in part by the BrightFocus Foundation grant G2014096, IUPUI DRIVE grant, and by an unrestricted grant from Research to Prevent Blindness. The DIGS and ADAGES studies were supported by National Institutes of Health grants P30EY022589, EY021818, EY11008, U10EY14267, EY019869, and by the Eyesight Foundation of Alabama, Alcon Laboratories, Inc., Allergan, Inc;, Pfizer, Inc., Merck, Inc., Santen, Inc., the Edith C. Blum Research Fund of the New York Glaucoma Research Institute (New York, NY), and by an unrestricted grant from Research to Prevent Blindness. The study reported in Swanson et al (2014) was supported by National Institutes of Health grants R01EY007716 (Swanson) and 5P30EY019008 (Indiana University School of Optometry). One of the authors (RM) received a portion of his funding from the Department of Health’s NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology. We thank Michael Wall and Randy Kardon for providing the control data for healthy eyes collected at University of Iowa Hospitals and Clinics.