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Y.-L. Chen, B. Tan, L. Shi, J. Lewis, M. Wang, K. Baker; The Shape of Aging Lens. Invest. Ophthalmol. Vis. Sci. 2010;51(13):4593.
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© ARVO (1962-2015); The Authors (2016-present)
This review compares published papers of ocular biometry to obtain a reference mathematical expression of aging lens.
We reviewed 36 recent research papers that present measured human lens parameters. Lens biometry was generally found to have little correlation with subjects’ refractive error. Accommodation and age are the two most prominent lens profile variables. Review of age dependence is performed on six parameters of relaxed eyes: the lens thickness, T, the radius of vertex curvature, R, and the asphericity or conic constant, Q, of both anterior and posterior surfaces, and the refractive index, n. Each parameter is examined and tabulated with the measurement methods, age range, gender, eye numbers, and age correlation conclusions. The age correspondence of each of the 6 parameters is plotted in same figure to compare studies. Possible sources of discrepancies from geographic factor, test methods, and systematic errors are examined.
Lens thickness is the most studied lens parameter. Systematic discrepancy between instruments was investigated by Atchison, Tong, and Koretz in ‘08, ‘02, and 1989 respectively, and a difference up to 0.2mm was estimated. Age dependence clearly shows the rapid decrease of thickness from ~4mm at infancy to minimum value ~3.4mm at 10 year old and then a subsequent slower increase with age. Age correlations of both anterior and posterior radii of curvature show the increase in childhood and decrease in adulthood with the peaks at puberties. These relationships are expressed with polynomial functions, and the coefficients are given in the table below. The very limited conic constant studies show insignificant correlation to age. Refractive index was reported in few papers. The age correlation in adults is small but significant.
Summary of the lens parameters are given in the table.
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