Characterization of optical aberrations: practical implementation of a Shack-Hartmann sensor with Matlab

Abstract

In cataract surgery, the clouded natural lens is replaced by an artificial lens called intra ocular lens (IOL). These lenses need to be correctly characterized for a successful surgery outcome, in order to avoid or compensate optical aberrations in the human vision system. In this thesis, an implementation of Shack-Hartmann wavefront reconstruction and characterization system is developed in MATLAB, with the objective to improve the performance of the standard software of a commercial sensor. Multiple approaches were implemented, focusing on optimizing correlation-based centroiding. Simulations were carried out to test the performance of different technique for noise cancelling and range extension, with a simple simulation environment developed in this thesis. Results show success on optimizing correlation-based centroiding, representing the closest technique to optimum in the majority of scenarios, and highlight the big impact that domain of reconstruction has in the system results. In conclusion, the system developed is flexible, implements a nice variety of options for adapting to different situations and provides the tools for testing and conducting research on the performance of Shack-Hartmann sensors. In addition, it is highly susceptible to modifications and improvements, and offers a solid alternative to the commercial sensor.