Anisoplanatism in adaptive optics compensation of human eye aberrations

The areas of adaptive optics application have increasingly expanded beyond astronomy over past ten years. One of the most striking examples is visual science. Fundus camera equipped with adaptive optics has been extensively investigated over past few years and employed with great success in obtaining fine images of the human retina in real time. But even if the aberrations of the human eye are corrected with adaptive optics the quality of retinal images is still degraded by anisoplanatism effect. We can obtain high-resolution image only if decorellation of the phase that is incident from the beacon on the retina and the point being imaged is small. The wavefront compensation is effective only within a finite area - the isoplanatic patch. On the basis of Zernike decompositions of the aberrated wavefront for different retinal angles we have been able to calculate the residual mean-square error for the corrected wavefront. We estimated the isoplanatic angle in human eye as the angular distance between the two sources where the mean-square error is equal to 1 square rad . Computer simulations illustrating the degrading effects of anisoplanatism on retinal imaging performance of adaptive optics system are presented. In the paper we discuss the limitations of isoplanatic patch enlargement by examining an ideal adaptive corrector that provides compensation of all Zernike modes. We simulated the blur of the retinal image induced by the eye's aberrations and the compensation of these aberrations by the corrector thus illustrating the performance of anisoplanatism-limited adaptive optics systems.