Surpassing the resolution limit of adaptive optics imaging in the living human eye by combining annular pupil illumination with sub-Airy disk confocal pinhole detection

High-resolution imaging is essential for understanding retinal diseases. Adaptive optics scanning light ophthalmoscopy (AOSLO) achieves cellular-level resolution through correction of the optical aberrations of the eye. However, the resolution of AOSLO is still limited by the diffraction of light. Here, we combine annular pupil illumination with sub-Airy disk confocal pinhole detection to surpass the diffraction limit. With the improved resolution, both rod photoreceptor and foveal cone mosaics were more readily identifiable in the living human eye.