PhD Thesis Defenses

Peripheral Optics of the Human Eye: Applied Wavefront Analysis

This thesis is dedicated to implementing wavefront analysis for studying the peripheral optics of the human eye with an emphasis on its relation to myopia. The aim is to find properties in the peripheral image quality. The work consists of the following main parts: • Literature review and analysis of population data on ocular aberrations of the relaxed eye over the horizontal visual field (Paper B). This paper recommends a method for the peripheral wavefront analysis and presents data for different groups of people: (a) population average, (b) myopic, and (c) emmetropic subjects. • Development of a novel, dual-angle, open field wavefront sensor (Paper D). The device enables recording of real-time, simultaneous fovealperipheral wavefront measurements, while providing a binocular open field of view. • Studying optical quality for myopic and emmetropic subjects under different accommodation demands (Paper F). The novelty of this work is the real-time accommodation state tracking, allowing a more accurate data analysis of both the dynamic and the average foveal and peripheral optical quality. • Using wavefront analysis to understand the contribution of optics to different aspects of peripheral human vision, such as resolution acuity and contrast sensitivity (Papers A, C, E). The results obtained in this work show the benefit of binocular viewing and real-time foveal measurements when studying peripheral aberrations under accommodation. With increasing accommodation, the relative peripheral refraction of myopic eyes becomes more negative, while the changes for the emmetropic eyes are small. However, the total peripheral optical quality proved to be similar between myopic and emmetropic subjects and varied little between distant and near objects. The results also suggest that the accommodative response is not the leading factor defining the magnitude of the microfluctuations in accommodation. Peripheral low contrast vision, irrespective of the foveal refractive error, is demonstrated to improve when monochromatic aberrations are corrected, while the effects of chromatic aberrations are negligible. Finally, the myopia control MiSight® multifocal contact lenses are shown to reduce vision performance in accommodation as well as in peripheral low-contrast resolution.