Abstract:
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Presbyopia starts to show up at the age of 40. The lens of the eye loses its flexibility to the point where we can no longer accommodate clearly in near vision. Progression-addition lenses correct the lack of accommodation and have three different zones: distance view, near view and intermediate zone, with a gradual change in power from the distance zone to the near zone. In geometrical terms, the optical power of a lens can be expressed as the difference between the principal curvatures of the surface lens, and the power can be expressed as the mean of the principal curvatures. The Minkwitz theorem states the apparition of unwanted astigmatism in the lateral zones of the lens, due to the change of power. This master thesis proposes a model for the design of progressive-addition lenses, taking into account the power lens and minimizing the unwanted astigmatism, as well as the gradient of astigmatism and the gradient of power. |