Purpose: traditional optical design is a numerical process based on ray tracing theory. The traditional method has the limitation of the application of the spectacle lens because of the necessity of initial configurations and the evaluations of the aberrations of the lens. This study is an initial attempt to investigate an analytic lens design method, Lagrange, which has a potential application in modern spectacle lens for eliminating the limitation of the traditional method. Methods: the Lagrange method can derive the differential equations of an optical system in term of its output and input. The generalized Snell???s law in three-dimensional space and the normal of a refracting surface in fundamental differential geometry are applied to complete the derivation. Based on the Lagrange method, the solution of a refracting surface to perfectly image a point at infinity is obtained. Results: a Plano-convex lens and a Bi-convex lens from this solution were designed. In spherical coordinates, the differential equations of the single surface system and its solution were obtained. The optical design software, ZEMAX, was used to simulate the lenses and evaluate their image qualities. The results illustrated that both of the two lenses were aberration free. Conclusions: the Lagrange solves unknown lens surface based on definable inputs and outputs according to customer requirements. The method has the potential applicants of the modern customized lens design. Moreover, the definable outputs make the simultaneous elimination of several aberrations possible.

Thesis (Ph.D.)--University of Alabama at Birmingham, 2008. / Title from PDF title page (viewed on July 15, 2010). Includes bibliographical references.

We present a miniature camera lens design method that uses a freeform surface based on the pedal curve to the ellipse in polynomial form. Two designs are presented and their benefits of optical performance and tolerance sensitivity are compared to designs with conventional aspheric surfaces. We also reverse a freeform design using even aspherical surfaces to show that the optimization solution of a freeform design cannot be reproduced by even aspherical surfaces.

Two experiments investigated the effects of pre-receptoral absorption and levels of illumination on colour vision. Simulation filters approximating lens and macular pigment changes were constructed on the basis of previous investigations. Experiment I investigated the effects of these filters on young, normal subject performance. Shifts were found in the direction of ageing populations but not as great as is required. Experiment II investigated the additional effect of reductions in illumination. The two experimental manipulations together account for senile decreases in discrimination at slightly higher levels than previously reported / Arts, Faculty of / Psychology, Department of / Graduate

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Yes / Purpose: To determine whether human ocular lens position is influenced by gravity. Methods: Anterior chamber depth and lens thickness were determined with a Haag-Streit Lenstar LS900 for right eyes of participants in two age groups, with a young group of 13 participants aged 18 to 21 years (mean 21 years, SD 1 year) and an older group of 10 participants aged 50 to 63 years (58 years, 4 years). There were two sessions for each participant separated by at least 48 hours, with one session for the usual upright head position and one session for a downwards head position. In a session, testing was done for minimum accommodation followed by testing at maximum accommodation. A drop of 2% pilocarpine nitrate was instilled, and testing was repeated after 30 minutes under minimum and maximum accommodation conditions. Results: Gravity, manipulated through head posture, affected anterior chamber depth for both young adult and older adult groups but mean effects were only small, ranging from 0.04 to 0.12mm, and for the older group required the instillation of an accommodation-stimulating drug. Gravity had a weakly significant effect on lens thickness for the young group without accommodation or a drug, but the effect was small at 0.04±0.06mm (mean±SD, p = 0.04). Conclusion: There is a small but real effect of gravity on crystalline lens position, manifested as reduction in anterior chamber depth at high levels of accommodative effort with the head in a downwards position. This provides evidence of the ability of zonules to slacken during strong accommodation.

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