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A.G. Tan, J.J. Wang, E. Rochtchina, P. Mitchell, Blue Mountains Eye Study; 6–Year Changes in Cross–Sectional Prevalence of Age–Related Cataract . Invest. Ophthalmol. Vis. Sci. 2005;46(13):3834.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To compare the prevalence of nuclear, cortical and posterior subcapsular cataract (PSC) in two population cross–section surveys of the Blue Mountains Eye Study (BMES) 6 years apart. Methods: BMES cross–section I (1992–4) recruited 3654 participants (82.4% of those eligible) and cross–section II (1997–2000) examined 3509 participants (75.1% of BMES survivors and 85.2% of newly eligible residents). Cataract was assessed during a masked grading of slit–lamp and retroillumination lens photographs using the Wisconsin Cataract Grading System. Cortical cataract was defined when cortical opacity comprised at least 5% of the lens area. Nuclear cataract was defined if nuclear opacity ≥ standard 4 of the Wisconsin System. PSC was defined when opacity comprised at least 1% of the lens area. Inter–grader reliability was assessed as high, with weighted kappa 0.53–0.79 for nuclear cataract grading, 0.64–0.82 for cortical and 0.48–0.82 for PSC grading respectively. A senior grader re–graded all nuclear cataract cases. Results: A comparison of the two survey populations showed that the mean age and sex distribution was similar. The prevalence of cortical cataract (23.8% in the 1st and 23.7% in the 2nd survey) and PSC (6.3% and 6.0%) was also similar. The prevalence of nuclear opacities increased from 18.7% to 27.7%, and cataract surgery prevalence increased from 6.0% to 7.9% over the period. After age standardization of the cross section II to cross section I populations, the relatively stable cortical (23.8% and 23.5%) and PSC (6.3% and 5.9%) cataract prevalence rates, and the increase in nuclear cataract (18.7% and 29.1%) and cataract surgery (6.0% and 7.7%) prevalence rates remained. We found a similar age–related increasing trend and gender differences in cataract prevalence in both surveys. Women had slightly higher prevalence of cortical and nuclear cataract than men, but the difference was only significant for cortical cataract (age–adjusted OR for women 1.3, 95% CI 1.1–1.5 and OR 1.4, CI 1.1–1.6 in the two surveys, respectively). In contrast, men had slightly higher PSC prevalence than women in both cross–sections. Conclusions: The data from two population cross–sections indicate a relatively stable prevalence of cortical and PSC cataract over a 6–year period, while suggesting a possible increased prevalence of nuclear cataract.
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