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Presbyopia, accommodation, and mature catenary

2002; Elsevier BV; Volume: 109; Issue: 8 Linguagem: Inglês

10.1016/s0161-6420(02)01138-7

1549-4713

William G. Ellis,

Mathematics and Applications

Coleman and Fish use an imprecise method for determining the radius of curvature. The calculation of radius of curvature using the formula given by the authors is critically dependent on the y values for the determination of a and b and must be equal. For example, a 10 μm difference between the measurement of the y values for a and b will result in approximately a 30% error in the calculation of radius of curvature. Radius of curvature is properly determined by curve fitting the surface and calculating the square of the regression coefficient to assess the fit. Once a good curve fit is obtained, the standard formula for radius of curvature as given is used: The authors should repeat their experiments using appropriate methods for calculating radius of curvature. It should be noted that the formula published by the authors is in error. The correct formula follows: 1Leithold L. The Calculus with Analytic Geometry. 2nd ed. Harper & Row, New York1972: 792-795Google Scholar Coleman and Fish use an imprecise method for determining the radius of curvature. The calculation of radius of curvature using the formula given by the authors is critically dependent on the y values for the determination of a and b and must be equal. For example, a 10 μm difference between the measurement of the y values for a and b will result in approximately a 30% error in the calculation of radius of curvature. Radius of curvature is properly determined by curve fitting the surface and calculating the square of the regression coefficient to assess the fit. Once a good curve fit is obtained, the standard formula for radius of curvature as given is used: The authors should repeat their experiments using appropriate methods for calculating radius of curvature. It should be noted that the formula published by the authors is in error. The correct formula follows: 1Leithold L. The Calculus with Analytic Geometry. 2nd ed. Harper & Row, New York1972: 792-795Google Scholar