Determining the imaging plane of a retinal capillary layer in adaptive optical imaging

Even in the early stage, endocrine metabolism disease may lead to micro aneurysms in retinal capillaries whose diameters are less than 10 μ. However, the fundus cameras used in clinic diagnosis can only obtain images of vessels larger than 20 μ in diameter. The human retina is a thin and multiple layer tissue, and the layer of capillaries less than 10 μ in diameter only exists in the inner nuclear layer. The layer thickness of capillaries less than 10 μ in diameter is about 40 μ and the distance range to rod&cone cell surface is tens of micrometers, which varies from person to person. Therefore, determining reasonable capillary layer (CL) position in different human eyes is very difficult. In this paper, we propose a method to determine the position of retinal CL based on the rod&cone cell layer. The public positions of CL are recognized with 15 subjects from 40 to 59 years old, and the imaging planes of CL are calculated by the effective focal length of the human eye. High resolution retinal capillary imaging results obtained from 17 subjects with a liquid crystal adaptive optics system (LCAOS) validate our method. All of the subjects' CLs have public positions from 127 μm to 147 μm from the rod&cone cell layer, which is influenced by the depth of focus.