Adaptive Optics Scanning Laser Ophthalmoscope using a Micro-electro-mechanical (MEMS) Deformable Mirror

摘要

A MEMS deformable mirror (DM)-based new generation adaptive optics scanning laser ophthalmoscope (AOSLO) has been developed for in-vivo microscopic imaging of the living human retina. With the miniaturized optical aperture of a μDMS-Multi™ MEMS DM made by Boston Micromachines Corporation (Watertown, MA), we were able to confine a compact and robust optical system to a mobile 30″x30″ breadboard while keeping the system aberrations diffraction-limited over an imaging field of view up to 3x3 degrees. A customized Shack-Hartmann wavefront sensor was devised to facilitate the MEMS DM based adaptive optics (AO) system. The ocular aberration is compensated over a 6mm pupil based upon a modal wavefront correction strategy. The AO correction is done for both ingoing and outgoing paths of the scanning laser ophthalmoscope. After AO correction, the root mean square wave aberration is reduced to less than 0.1μm for most eyes. The lateral resolution is effectively enhanced and the images reveal clear cone mosaic near the foveal center. The significant increase of the throughput at the confocal pinhole allows for a confocal pinhole whose diameter is less than the Airy disc of the collection lens, thereby fully exploiting the axial resolution capabilities of the system. The MEMS DM as well as its successful application represents the most significant technological breakthrough of this new generation AOSLO.