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.
