Accurate fixation of adaptive optics fundus imaging field of view based on visual target guidance

For the high imaging resolution of the adaptive optics (AO) fundus camera and the existence of the eye isoplanatic angle, a single adaptive optics imaging field of view was limited to 1 . To get a complete fundus image, accurate fixation of one single field of view and image mosaicking of multiple fields of view must be achieved. In order to accurately track fundus imaging area, the principle to guide imaging field of view with a visual target was analyzed and a novel visual target system was designed. Parallel light was used to illuminate the target and focused to the center of the human pupil through a lens before the eye. In this way, the retinal position of the imaging field of view could be precisely measured. The visual target guidance system was introduced into a liquid crystal adaptive optics camera. The imaging field ranged to 22.6on the retina. The fixation accuracy was achieved to 0.003. This set of adaptive optics system successfully tracked single retinal photoreceptor cell and got stitched images of fundus blood vessels, which was beneficial for application and popularization of liquid crystal AO system in clinical ophthalmology.