Patent attributes
A photographic stop with two apertures is disposed at a position substantially conjugate to the anterior ocular segment of the eye being examined and at a position on the object-side focal surface of an image-forming lens. An eye fundus image is guided via a lattice barrier disposed on the image-side focal surface of the image-forming lens to an imaging CCD. The photographic stop, image-forming lens, lattice barrier and CCD are moved as a unit for focus adjustment. With such a configuration, the photographic stop is always positioned upon the object-side focal surface of the image-forming lens with the optical system kept telecentric even when the focus is adjusted to compensate for differences in diopter of the eye. This eliminates the phenomenon of a stereoscopic view that becomes more concave or convex the nearer to the periphery of the screen and provides good images of the fundus for stereoscopic viewing without any crosstalk of the left and right fundus images upon the image pickup surface.
