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The proposed instrument was specified to provide a fundus view and steerable fixation over a 30° FOV, with a spectacle sphere correction range of -20 to +10 diopters (D). Finally, we demonstrate the assembled and fully functional instrument, and include the measurement of various performance metrics. Next, a description of the design of each of the instrument’s subsystems, including optical and mechanical tolerance analysis is provided.
16141 high tor dr full#
In what follows we outline the system specifications and first order layout of the full optical system. Both the fixation and imaging arms of the instrument partially correct the longitudinal chromatic aberration (LCA) and spherical aberration of the average human eye. The instrument was designed with an unusually long eye relief to allow integration with reflective adaptive optics ophthalmoscopes. This will in turn facilitate the montaging of AO retinal images, which is a well-recognized problem and currently a challenge for longitudinal imaging. In addition to assisting and validating the fixation steering, and by allowing a small fraction of the AO ophthalmoscope light to reach the camera, the fundus pictures provide an accurate record of the AO ophthalmoscope FOV location. Here, we propose an instrument that combines an internal fixation target with a near infrared fundus camera as a viewfinder. Fixation targets have also been demonstrated and whether internal or external, are only a partial solution in that they do not address changes in fixation locus due to disease. Various solutions have been proposed and demonstrated to address this problem, including the use of a wide-field ophthalmoscope with an AO scanning light ophthalmoscope (AOSLO), or by temporarily increasing the AO ophthalmoscope’s FOV. Steering such a small FOV to the retinal region of interest using just a live image from the AO ophthalmoscope itself presents important practical challenges due to involuntary eye motion and retinal pathology. Current high-resolution adaptive optics (AO) ophthalmoscopes have a 1-3° field of view (FOV), due to the size of the isoplanatic angle of the human eye which varies across individuals and with pupil diameter.