Yasuyuki Numajiri

A compact adaptive optics scanning laser ophthalmoscope with high-efficiency wavefront correction using dual liquid crystal on silicon - spatial light modulator

This paper describes a compact adaptive optics scanning laser ophthalmoscope (AO-SLO) for high-resolution retinal imaging. The key features of this system are: (1) incorporation of a dual liquid crystal on silicon spatial light modulator (LCOS-SLM) as a wavefront compensation device and (2) sequential processing of aberration measurement/compensation and SLO imaging. The dual LCOS-SLM can compensate higher order aberration with high stabilization and realizes high-efficiency wavefront correction without polarization dependence. The sequential processing can fully utilize the power of the light to a retina only for the imaging, so the system produces high-contrast SLO images. The sequential processing also enables the use of lenses in ocular optics, giving a compact optical system with focus correction lenses for an eye with high reflective error. The optical system occupies only 500 mm x 370 mm, which is achieved by axially symmetric aspherical mirrors arranged off-axis and lenses in ocular optics. With this system, it is possible to observe photoreceptors at the parafoveal region of human healthy subjects at 32 or 64 frames per second.