Abstract

Structural parameters of the cone mosaic of the human fovea have usually been obtained by histological in vitro methods, in which results can differ somewhat from the actual values of the living eye. More recently, in vivo estimations have been obtained by psychophysical methods. Here, we present an objective method that allows, for the first time, in vivo high resolution measurements of the cone mosaic topography. The method is similar to stellar speckle interferometry used in astronomy to resolve binary stars through atmospheric turbulence. We have obtained short-exposure speckle images of a small area of the fovea. From here, after selecting the best specklegrams, we have computed the average power spectrum, which contains spatial frequencies as far as the diffraction limit of the eye. As the pupil natural diameter was >7 mm and the wavelength was 0.63 µm, the resolution obtained was better than 0.3 min of arc. By applying this method, we have obtained, for a normal young subject, an intercenter cone distance of 0.51 ± 0.02 min of arc, corresponding to ~2.45 µm.

© 1989 Optical Society of America