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Liew G.,University of Sydney | Wang J.J.,University of Sydney | Wang J.J.,University of Melbourne | Wang J.J.,Center for Vision Research
Revista Espanola de Cardiologia | Year: 2011

There is increasing recognition that coronary microvascular dysfunction also plays an important role in coronary heart disease. Little is known about this aspect of coronary heart disease due to difficulties in studying the coronary microcirculation directly. The retina is a unique site where the microcirculation can be imaged directly, providing an opportunity to study in vivo the structure and pathology of the human circulation and the possibility of detecting changes in microvasculature relating to the development of cardiovascular disease. This review covers the recent progress in research linking retinal vascular signs to coronary heart disease, and finds accumulating evidence that retinal vascular signs may provide a window into the health of the coronary microvasculature. The most widely studied signs, arteriolar narrowing, and more recently, venular dilation, are likely associated with increased risk of coronary heart disease in women, independent of traditional risk factors. Attempts to improve coronary heart disease risk prediction by incorporating retinal vessel calibre size into risk prediction scores complementing traditional algorithms such as the Framingham risk scores have so far been disappointing. Research is ongoing into the predictive utility of other retinal vascular signs. Retinal photography provides long-lasting records that enable monitoring of longitudinal changes in these retinal signs and vascular health. © 2010 Sociedad Española de Cardiología. Published by Elsevier España, S.L. All rights reserved. Source

Tariq Y.M.,University of Sydney | Li H.,University of Sydney | Burlutsky G.,University of Sydney | Mitchell P.,University of Sydney | Mitchell P.,Center for Vision Research
Eye (Basingstoke) | Year: 2012

PurposeTo determine normative values and associations of retinal nerve fiber layer (RNFL) and optic disc parameters in normal eyes measured by spectral domain optical coherence tomography (OCT).MethodsIn a population-based setting, 1521 young adults were examined as part of the Sydney Adolescent Vascular and Eye Study (SAVES). Their mean age was 17.3±0.6 years. RNFL and optic disc parameter measurements were made using Cirrus HD-OCT 4000.ResultsThe average RNFL was found to be 99.4±9.6μm. RNFL thickness was least for the temporal quadrant (69.9±11.2μm), followed by the nasal (74.3±12.8μm), superior (124.7±15.7μm) and inferior (128.8±17.1μm) quadrants. The mean disc area in this population was 1.98±0.38mm 2 with a mean rim area of 1.50±0.30mm 2 and a mean cup-disc ratio of 0.44±0.18. Multivariate-adjusted RNFL thickness was marginally greater in East Asian than in white participants (100.1μm vs 99.5μm; P=0.0005). The RNFL was thinner with greater axial length (P<0.0001), less positive spherical equivalent refractions (P<0.0001), smaller disc area and rim area (P<0.0001).ConclusionThis study documents normative values for the RNFL and optic disc measured using Cirrus HD-OCT in young adults. The values and associations reported in this study can inform clinicians on the normal variation in RNFL and optic disc parameters. © 2012 Macmillan Publishers Limited All rights reserved. Source

Pai A.S.-I.,Center for Vision Research | Wang J.J.,Center for Vision Research | Wang J.J.,University of Melbourne | Samarawickrama C.,Center for Vision Research | And 6 more authors.
Ophthalmology | Year: 2011

Purpose: To assess the prevalence and associations of visual impairment (VI) in preschool children. Design: Cross-sectional, population-based study. Participants: A total of 2461 children (73.8% participation rate), aged 6 to 72 months, were examined in the Sydney Paediatric Eye Disease Study during 20072009; of whom 1188, aged 30 to 72 months, with complete visual acuity (VA) data in both eyes, were included in this report. Methods: Measurement of VA was attempted on all children using the Electronic Visual Acuity (EVA) system or a logarithm of the minimum angle of resolution (logMAR) chart. Visual impairment was defined as presenting VA <20/40 in children aged <48 months and <20/50 in those aged <48 months. Post-cycloplegic refraction was measured, and myopia was defined as spherical equivalent (SE) ≤-0.50 diopters (D), hyperopia was defined as SE <2.00 D, astigmatism was defined as cylinder <1.00 D, and anisometropia was defined as SE difference <1.00 D between 2 eyes. Ethnicity, birth parameters, and sociodemographic information were collected in questionnaires completed by parents. Main Outcome Measures: Visual impairment prevalence and its associations with child demographic factors and birth parameters. Results: Visual impairment was found in 6.4% of the worse eye and 2.7% of the better eye in our sample. Refractive errors (69.7%) and amblyopia (26.3%) were the principal causes of VI in the worse eye. Astigmatism (51.3%) and hyperopia (28.9%) were the main refractive errors causing VI. In regression analysis controlling for other factors, VI was independently associated with low birthweight of <2500 g (odds ratio 2.4, 95% confidence interval, 1.15.3), but not with age, gender, ethnicity, or measures of socioeconomic status (P > 0.05). Conclusions: Visual impairment in at least 1 eye was found in 6.4% of Australian preschool children, with bilateral VI found in 2.7%. Uncorrected refractive errors and amblyopia were the principal ocular conditions associated with VI. Low birthweight was a significant risk factor independent of age, gender, and ethnicity. Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article. © 2011 American Academy of Ophthalmology. Source

Le A.,University of Toronto | Vesia M.,University of Toronto | Yan X.,Center for Vision Research | Niemeier M.,University of Toronto | And 3 more authors.
Cerebral cortex (New York, N.Y. : 1991) | Year: 2014

Grasping with 2 limbs in opposition to one another is older than the hand, yet the neural mechanisms for bimanual grasps remain unclear. Similar to unimanual grasping, bimanual grasping may require regions in the parietal cortex that use visual object-feature information to find matching stable grasp points on the object. The localization of matching points is computationally expensive, so it might make sense for the signals to converge in a single cortical area. To examine this, we use transcranial magnetic stimulation (TMS) to probe the contribution of cortical areas known to be associated with unimanual grasping, while participants performed bimanual grasps. We applied TMS to the anterior and caudal portion of the intra-parietal sulcus (aIPS and cIPS) in each hemisphere during a size-perturbation task using the index fingers of both hands to grasp an object whose orientation might or might not change. We found significant interaction effects between TMS and perturbation of the grasp-relevant object dimension that increased grip aperture only for the right aIPS. These results indicate that the aIPS is involved not only in unimanual, but also bimanual grasping, and the right aIPS is critically involved in bimanual grasps. This suggests that information from both hemispheres converges in the right hemisphere to achieve bimanual grasps. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com. Source

Kanthan G.L.,University of Sydney | Mitchell P.,University of Sydney | Burlutsky G.,University of Sydney | Wang J.J.,University of Sydney | And 2 more authors.
American Journal of Ophthalmology | Year: 2010

PURPOSE: To assess whether alcohol consumption is associated with the long-term incidence of cataract or cataract surgery. DESIGN: Population-based prospective cohort study. METHODS: A total of 3654 persons aged 49+ years were examined at baseline and 2564 were re-examined after 5 and/or 10 years. Lens photographs were taken at each visit and assessed using the Wisconsin Cataract Grading System by masked graders. An interviewer-administered questionnaire was used to collect information on alcohol consumption. RESULTS: No significant associations were observed between alcohol consumption and long-term risk of nuclear, cortical, and posterior subcapsular cataract. However, after adjusting for age, gender, smoking, diabetes, myopia, socioeconomic status, and steroid use, total alcohol consumption of over 2 standard drinks per day was associated with a significantly increased likelihood of cataract surgery, when compared to total daily alcohol consumption of 1 to 2 standard drinks (adjusted odds ratio [OR] 2.10, 95% confidence interval [CI] 1.16-3.81). Abstinence from alcohol was also associated with increased likelihood of cataract surgery when compared to a total alcohol consumption of 1 to 2 standard drinks per day (adjusted OR 2.36, 95% CI 1.25-4.46). CONCLUSION: A U-shaped association of alcohol consumption with the long-term risk of cataract surgery was found in this older cohort: moderate consumption was associated with 50% lower cataract surgery incidence, compared either to abstinence or heavy alcohol consumption. © 2010 Elsevier Inc. All rights reserved. Source

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