Tunable lenses are optical systems that have attracted much attention due to their potential applications in such areas like ophthalmology, machine vision, microscopy and laser processing. In recent years we have been working in the analysis and performance of a liquid-filled variable focal length lens, this is a lens that can modify its focal length by changing the amount of water within it. Nowadays we extend our study to a particular adaptive lens known as solid elastic lens (SEL) that it is formed by an elastic main body made of Polydimethylsiloxane (PDMS Sylgard 184). In this work, we present the design, simulation and analysis of an adaptive solid elastic lens that in principle imitates the accommodation process of the crystalline lens in the human eye. For this work, we have adopted the parameters of the schematic eye model developed in 1985 by Navarro et al.; this model represents the anatomy of the eye as close as possible to reality by predicting an acceptable and accurate quantity of spherical and chromatic aberrations without any shape fitting. An opto-mechanical analysis of the accommodation process of the adaptive lens is presented, by simulating a certain amount of radial force applied onto the SEL using the finite element method with the commercial software SolidWorks ® . We also present ray-trace diagrams of the simulated compression process of the adaptive lens using the commercial software OSLO ® .

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Misalignments are a common problem in corneal topography reconstruction. To determine the topography of the surface using a corneal topographer based on the null-screen method, it is necessary to measure errors caused by mechanical misalignment of the topographer, which could influence the results of this technique but are not related to the quality of the corneal surface. To evaluate the variability in measurements, in this work, we simulate some misalignments in the optical system, for the simulation we design a semi-radial null-screen to test a reference spherical surface to identify the variations in results introduced by misalignment errors of the corneal topographer with respect to the test surface. According to the simulations, the accuracy of the null-screen method ranges from 0.81 µm to 2.84 µm for typical tilt, decentering, and defocusing errors. Experimental results for the testing of a spherical surface are shown. After removing the misalignments, we found that the variations are approximately 3.5 μm rms value measured with respect to the best-fitting sphere, and the radius of curvature differs approximately 0.06% from the design value.

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