Abstract: Slit lamp having a slit illumination system, a binocular microscopic system and a photographing system. The binocular microscopic system has an objective lens assembly which is mounted replaceably on the body. A replaceable lens unit is provided for observation of the endothelial cell of the cornea. The lens unit include an objective lens, a relay lens and mirrors for directing the light bundle through the objective lens to one of the optical paths in the binocular microscopic system.

Abstract: A slit lamp microscope includes an illumination light source from which light is passed through two separate optical paths to the patient's eye. The first of the optical paths includes a slit mask and a projecting lens so that the light is focused on the patient's eye to provide a bright slit-like illumination. The light which has passed through the second path provides a uniform auxiliary illumination around the illuminated slit area so that the location of the area can be readily determined with respect to other portions of the patient's eye.