Reflective broadband adaptive optics scanning light ophthalmoscope with 20 D focus range.

Here we present an adaptive optics scanning light ophthalmoscope with a square 1.5° full field of view, steerable within a 4° window. When imaging through a 7.72 mm diameter pupil, the instrument provides nominal diffraction-limited performance at the retinal conjugate over a 20 diopter (D) focus range centered at 1D of myopia and supports a 3 D source-detector vergence range for any combination of wavelengths between 450 and 1300 nm. The optical setup also provides nominal diffraction-limited imaging between the pupil conjugates of the wavefront sensor, deformable mirror, and eye, with distortion below 0.5% across the 3 D source-detector vergence range. The optical setup includes four pupil relays. The first three are telescopes formed by pairs of concave spherical mirrors tilted in a non-planar configuration. In these relays, the mirror-to-mirror spacing was held fixed, while the distances to the entrance and exit pupil planes were varied to mitigate aberrations in both pupil and retinal conjugates. The fourth relay comprises four spherical mirrors, two concave and two convex, tilted in a planar configuration. As-built instrument performance is demonstrated by imaging a telecentric model eye over a -6 to +8 D range (limited by deformable mirror stroke) and human photoreceptor mosaic imaging at 680 and 795 nm. The proposed relay forms are broadly applicable to adaptive optics ophthalmoscopes and imaging modalities, including fluorescence, spectroscopy, and optical coherence tomography.