Optic nerve head morphology in glaucoma patients of African descent is strongly correlated to retinal blood flow.

BACKGROUND/AIMS: To examine the relationship between change in optic nerve head (ONH) morphology and retinal blood flow in patients with open-angle glaucoma (OAG) of African (AD) and European descent (ED) over 3 years. METHODS: 112 patients with OAG (29 AD; 83 ED) underwent assessment of ONH morphology using Heidelberg retinal tomography (HRT-III), and retinal blood flow using confocal scanning laser Doppler. Repeated-measures analysis of covariance was used to compare baseline and 3-year measurements, and Pearson correlations were calculated to evaluate the relationships. RESULTS: In OAG patients of AD, change in superior mean retinal blood flow was strongly, negatively correlated with change in cup/disc (C/D) area ratio (r=-0.78, p=0.020) and cup area (r=-0.75, p=0.0283) and strongly, positively correlated with change in rim area (r=0.74, p=0.0328) over 3 years. In OAG patients of AD, change in inferior mean retinal blood flow was strongly, negatively correlated with changes in C/D area ratio (r=-0.88, p=0.0156) and linear C/D ratio (r=-0.86, p=0.0265) over 3 years. In OAG patients of ED, these correlations were weak and did not reach statistical significance. DISCUSSION: OAG patients of AD may have a stronger vascular component to their glaucoma pathophysiology than patients of ED.

Vascular considerations in glaucoma patients of African and European descent.

Glaucoma is the leading cause of blindness in individuals of African descent (AD). While open-angle glaucoma (OAG) disproportionately affects individuals of AD compared with persons of European descent (ED), the physiological mechanisms behind this disparity are largely unknown. The more rapid progression and greater severity of the disease in persons of AD further raise the concern for identifying these underlying differences in disease pathophysiology between AD and ED glaucoma patients. Ocular structural differences between AD and ED patients, including larger optic disc area, cup:disc ratio and thinner corneas, have been found. AD individuals are also disproportionately affected by systemic vascular diseases, including hypertension, cardiovascular disease, stroke and diabetes mellitus. Abnormal ocular blood flow has been implicated as a risk factor for glaucoma, and pilot research is beginning to identify localized ocular vascular differences between AD and ED OAG patients. Given the known systemic vascular deficits and the relationship between glaucoma and ocular blood flow, exploring these concepts in terms of glaucoma risk factors may have a significant impact in elucidating the mechanisms behind the disease disparity in the AD population.

Cerebrospinal fluid pressure and glaucoma: regulation of trans-lamina cribrosa pressure.

Increased trans-lamina cribrosa pressure difference (TLCPD), the difference of intraocular pressure (IOP) and orbital cerebrospinal fluid pressure (CSF-P), has been investigated as a possible risk factor in glaucoma pathogenesis. In fact, lower CSF-P in the setting of normal IOP has been implicated as a potential risk factor for normal tension glaucoma. Increased TLCPD has been associated with decreased neuroretinal rim area and increased visual field defects. Furthermore, dysregulation of systemic blood pressure has been associated with changes in IOP. Recent studies have also suggested that increased body mass index (BMI) is associated with decreased prevalence of glaucoma, which may be due to an increased CSF-P with increased BMI found in many studies. Given the interaction of various pressures, their role in glaucoma pathophysiology has come under investigation and warrants further study in order to better understand the aetiology and progression of glaucoma.

Characterization of clinical study populations by race and ethnicity in biomedical literature.

OBJECTIVE: The importance of race and ethnicity in biomedical research has long been a subject of debate, recently heightened by data revealed by the completion of the sequencing of the human genome and the mapping of human genetic variation. We aimed to determine whether and how the reporting of race has changed over the last three decades and how the practice may differ given study location, where the journal of publication is based, and decade of publication. DESIGN: We analyzed a sample of studies published in the Journal of the American Medical Association, The Lancet, and the Canadian Medical Association Journal from 1980 to 2009. MAIN OUTCOME MEASURES: The number of articles that reported race by journal and decade and the descriptors used. RESULTS: Of 1867 articles analyzed, 17.30% reported race. The reporting of race and number of populations reported increased over time for all three journals. In addition, the diversity of race/ethnicity descriptors increased, with increased use of race/ethnicity combinations and nationality of research subjects. CONCLUSION: Though it has increased over the past few decades, the reporting of race/ethnicity of study populations is relatively low, ambiguous and inconsistent, likely influenced by the uncertain relevance of these variables to the study's outcomes, study location, researcher views, and the policies of journals and funding agencies. Thus, due to the inconsistent and ambiguous practice of reporting race/ethnicity, comparison of study outcomes can result in misleading conclusions. Improvements in standardization of terms and new approaches to characterize research participants related to race/ethnicity are imperative.