Photography of lens opacities by trans-scleral illumination.

FINCHIAM (1955) discussed the value ofphotographically recording the progress of cataract and described a method whereby lens opacities were photographed by the light reflected from the fundus by trans-pupillary trans-illumination. A slit lamp was used, in which the axis of illumination was coincident with the line of observation; the mirror of the illuminating system was replaced by a thin glass plate and the microscope by a single lens reflex camera. With this method, lens opacities were seen as dark areas against the luminous background of the fundus, and contrast was increased with a dark orange filter in the illuminating or camera system. Previously, Douvas and Allen (1950) had photographed lens opacities with the Nordenson retinal camera; in their photographs opacities also showed as dark areas against the retinal reflex. In the method now to be described the cataract is focally illuminated by light introduced into the eye through the lower lid and sclera; reflected light from the fundus is kept to a minimum, and the lens opacity is seen as a white area against the dark fundus background.