![]() It is anticipated that mainland China alone will have 631 million people older than 50 years in 2050. Acute angle closure is likely to increase over the coming decades as the populations of these countries age. 7, 8 Incidence increases with age and is more common among women, with an incidence of 68.5/100 000 per year among Chinese women older than 60 years. 1 - 3 Singapore has one of the highest rates of AAC in the world with an islandwide incidence estimated at 12.2/100 000 per year in the population older than 30 years. 6Īcute angle closure (AAC) accounts for about 20% of PACG and frequently results in severe vision loss. 1, 2 Given that almost half of the world's population lives in China and India, millions of individuals are at risk of PACG. 1, 2 The rates of visual impairment and blindness from PACG are likely 2 to 3 times those of open-angle glaucoma. 1 - 5 Chinese subjects in Singapore and a southern Indian population both had high rates of PACG in recent population-based studies, with about 1% of the individuals older than 40 years having PACG. PRIMARY ANGLE-CLOSURE glaucoma (PACG) is a leading cause of world blindness, with higher rates documented in Asian populations. Dynamic measures of the response to luminance changes and pilocarpine therapy indicate that differential reactions to these stimuli are also associated with an AAC attack. ![]() These static measures of ocular biometry indicate why some individuals are predisposed to AAC. Dynamic testing showed that the angle of control eyes tended to shallow less when going from light to dark and tended to open more when given 1 drop of pilocarpine hydrochloride.Ĭonclusions Contralateral eyes of individuals having an AAC attack tend to be shorter and have more crowded anterior segments than those of healthy controls. Scheimpflug photographs revealed an adjusted angle width of 21.6° for controls and 15.1° for cases ( P<.05). Adjusting for age and sex, the mean angle-opening distance at 500 µm was 0.14 U less for cases, with a mean of 0.26 U in controls, making the angle-opening distance at 500 µm, on average, 54% less among cases. Furthermore, using multiple logistic regression to adjust for age and sex, patients with primary angle-closure glaucoma were 19 times as likely to have a shallower limbal anterior chamber depth (25% 95% confidence interval, 8.3-45.2). After adjusting for age and sex, cases had a mean adjusted axial length that was 1.2 mm shorter, an optical anterior chamber depth that was 0.63 mm shallower (24% shallower than controls), and lenses that were, on average, 0.35 mm thicker ( P<.01). Results Contralateral eyes of cases of AAC had shorter axial lengths, shallower anterior chamber depths, thicker lenses, and steeper radii of corneal curvature( P<.01). Scheimpflug photography produced a single measure of angle width. ![]() Ultrasonographic biomicroscopy parameters that include the angle-opening distance at 500 µm and the angle-recess area were noted. Main Outcome Measures Ocular biometric parameters including anterior chamber depth, limbal anterior chamber depth, axial length, lens thickness, and radius of corneal curvature were obtained. Methods Slitlamp assessment, ultrasonographic biomicroscopy, Scheimpflug photography, and provocative testing were performed. Participants Chinese persons seen as incident cases of AAC and Chinese population-based controls. Objectives To compare ocular biometry of the contralateral eyes of individuals seen with acute angle closure (AAC) with eyes of population-based control subjects, and to assess novel provocative tests to study the mechanism of AAC. Shared Decision Making and Communication.Scientific Discovery and the Future of Medicine.Health Care Economics, Insurance, Payment.Clinical Implications of Basic Neuroscience.Challenges in Clinical Electrocardiography.
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