A confocal laser scan microscope is designed for the diagnosis and the examination of the anterior segment of the human eye in vivo. Any contact of the eye with the instrument optics or an immersion fluid is avoided to preclude the risk of infection or injury. Normal eyes of nine volunteers are observed and investigated. Nerve fibers and keratocytes in the stroma and the endothelium of the cornea, the capsule, and the suture of the lens, and threadlike structures in the vitreous can be observed. Cellular details in all tissues investigated can be resolved.