Correction of the Aberrations of the Eye Using Adaptive Optics with Pupil Tracking

Abstract

Adaptive optics has long been used in the astronomical telescopes to acquire high resolution images via the real time correction of the rapidly changing wavefront aberrations. Human retinal images also suffer from rapidly changing aberrations due to, for example, eye movements, crystalline lens fluctuations or changes in the tear film. Several research groups in the world have used adaptive optics for different retinal imaging modalities and were able to acquire high resolution images of the human retina revealing the photoreceptor mosaic. Being able to image human retina in high resolution opens a new era in many important fields, such as pharmacological research for retinal diseases, researches in human cognition, nervous system, metabolism and blood stream to name a few. Having such a potential in medicine, there is not an available commercial adaptive optics retinal imaging system for clinical research and practice yet. The reasons are the complexity, cost and poor reliability of the available systems of the research groups. Here in this research our aim was to search a cost effective way of improving the adaptive optics correction of a compact adaptive optics retinal imaging system designed for clinical research. Based on the hypothesis that majority of the changes in the aberrations of the eye are due to eye movements, using the default eye camera that is used for the alignment of the eye in the retinal imaging system, the new method required no extra cost or hardware. It was possible to control the deformable mirror in real time based on pupil tracking measurements and correct for the aberrations of a moving model eye and in vivo. As an outcome of this research we showed that pupil tracking which is an indispensable tool for retinal imaging in high resolution can be effectively used as a part of the adaptive optics as a result of the fact that indeed eye movements constitute an important part of the ocular wavefront dynamics.