A pupil tracking system for adaptive optics retinal imaging

High-resolution imaging of the retina is a challenge due to the optical aberrations introduced by the eye, a living system in constant change and motion. Adaptive Optics (AO) is particularly suited to the continuous, dynamic correction of aberrations as they change over time. In particular, eye pupil displacements induce fast-changing wave front errors which lead to a need for faster wave front sensors. We propose a new approach for ocular adaptive optics by adding a Pupil Tracking System (PTS) into the AO loop. This system is different from the existing eye tracking devices by its speed, high precision in a short range and therefore its suitability for integration in an AO loop. Performance tests done using an artificial eye with a pupil diameter of 7 mm have shown promising results. These tests have demonstrated that the device achieves an accuracy of <15 μm in a ±2 mm range of eye movements with a standard deviation <10 μm, and requires less than 12 ms for each detection.

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