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Campbell C.E.,2908 Elmwood Court
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2011

It was found in Part 1 of this paper [J. Opt. Soc. Am. A 28, 2148 (2011)] that only variable power optical effects that can be described by quadratic functions can be formed by laterally translating two-element variable power lenses. In the case of rotationally translating two-element variable power lenses, possible designs are found by mapping possible laterally translating designs from a Cartesian space to the polar coordinate space of the rotationally translating lens. Several designs that have been manufactured or suggested theoretically are examined in Part 2 to see which ones are true variable power lenses. © 2011 Optical Society of America. Source


Campbell C.E.,2908 Elmwood Court
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2011

The conditions under which a two-element variable power lens can be created are examined. Such a lens is defined as one in which the functional form of the optical effect created does not change as the elements translate with respect to one another-only the magnitude of the effect changes. It is found that only variable power optical effects that can be described by quadratic functions can be formed by laterally translating two-element variable power lenses. In the case of rotationally translating two-element variable power lenses, possible designs are found by mapping possible laterally translating designs from a Cartesian space to the polar coordinate space of the rotationally translating lens. © 2011 Optical Society of America. Source


Campbell C.E.,2908 Elmwood Court
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2010

on the known way in which the lens grows throughout its life, on the measured characteristics of the lens surfaces as a function of the age of the lens, on the measured changes in the shape of the lens during accommodation, and on measured material characteristics of the lens materials, such as density and index of refraction throughout. The observed changes in central surface curvature and thickness force the shell thicknesses to vary in a predicable way and in turn force the shell surface asphericity to take certain values. Thus, in addition to giving the shape of each shell, the model predicts the change expected in the asphericity of the lens surfaces as the lens ages and adds cortical cell layers. Two examples are given, one for a 25-year-old lens and one for a 40-year-old lens, to show how the cortical layers change their shapes throughout the cortex and over time as the lens ages. The performance of the model of this paper is compared to that of two other nested shell models, one where the layers have constant thickness and one where the lens posterior is fixed within the eye over time, to show the superior performance of this model with respect to maintaining a constant refractive error for the eye as the lens ages and grows. © 2010 Optical Society of America. Source


Campbell C.E.,2908 Elmwood Court
Journal of the Optical Society of America A: Optics and Image Science, and Vision | Year: 2010

The relative importance of the various optical elements of the human eye are analyzed to determine which contribute most to the chromatic variance in total refractive power of the eye. The concept of differential dispersion, defined as the change in the difference in index of refraction across a refractive surface with change in wavelength, is used to provide a theoretical tool for this analysis. The theoretical treatment shows that almost all the chromatic effect will be caused by the air-tear interface. Calculations of model eyes are made that support this view. Four model eyes are examined, an emmetropic eye, a hyperopic eye, a myopic eye, and an emmetropic eye accommodating 2.5 D. © 2010 Optical Society of America. Source

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