Polychromatic adaptive optics to evaluate the impact of manipulated optics on vision

The eye is an optical instrument that projects scenes of the visual world onto the retina. However the human eye is far from being a perfect optical system, and, as a consequence, the images projected on the retina are blurred by ocular aberrations, as well as diffraction and scattering. Therefore in the last years, multiple technologies based on wavefront sensing and Adaptive Optics (AO) have been developed for the measurement and correction of ocular aberrations. As a result important knowledge has been gained on the contribution of the different components of the eye to the degradation of image quality. However the processes underlying neural adaptation to ocular aberrations are not yet well understood. Understanding the effects of a particular low order aberration, astigmatism, is particularly attractive to investigate adaptive processes in the visual system due to the inherent oriented nature of the blur that it produces. Typically, the impact of ocular aberrations on vision is studied using wavefront sensors with monochromatic, generally infrared, light. However, the retinal image quality is degraded by the presence of both monochromatic and polychromatic aberrations in the ocular optics. The study of the impact of retinal image quality on vision should therefore consider both the aberrations in the visible light, as well as the effect of chromatic aberrations. In addition optical and structural properties of the eye change with age and with certain ocular conditions and treatments, altering the natural aberrations, as well as the interactions between monochromatic and chromatic aberrations, and consequently the visual function. xvi Summary of the thesis The understanding of the interactions of these aberrations and their effect upon correction is essential to explore the limits of human spatial vision, and to design and optimize new alternatives of correction of Presbyopia/Myopia and more complex individualized refractive corrections. In this thesis we have used AO techniques to study the effect of specific monochromatic aberrations and their combinations on vision, to test neural adaptation to those aberrations and their correction, to measure chromatic aberrations of the eye in normal and pseudophakic eyes, and to test vision with simulated multifocal solutions for Presbyopia