Adaptive optics for high-resolution imaging of the living human retina

Summary form only given. The resolution limit imposed by the aberrations of the eye generally prohibits imaging structures in the living retina the size of single cells. Though it is possible to correct defocus and astigmatism with spectacle lenses, additional aberrations such as coma, spherical, and higher order aberrations remain. The authors have constructed an adaptive optical system that measures the wave aberration of the eye and compensates for it with a deformable mirror. A Hartmann-Shack wavefront sensor measures the local slopes of the wavefront in the pupil plane produced by a point source on the retina. The wave aberration is calculated from the wavefront slopes with a least squares technique. The authors compensate for the wave aberration with a deformable mirror that has 37 actuators with each 3-/spl mu/m stroke (Xinetics, Inc.). In one subject with a 6-mm pupil and 632.8-nm light, adaptive compensation reduced the peak to peak-phase error from 2.9 /spl mu/m to less than 0.5 /spl mu/m. A figure shows the retinal point spread function in this subject calculated from the wave aberration when no adaptive correction had been made. Defocus and astigmatism have been removed from the wave aberration because they can be corrected with spectacle lenses.