A new, nonapplanating, real-time slit scanning confocal microscope is described for the in vivo examination of the living human eye. This confocal microscope produces unique real- time video images of the in vivo human cornea. In contrast to other confocal microscopes designed for in vivo ocular imaging, which are based on either the Nipkow disk (pinholes) or the modified wide-field specular microscope (photographic system which is not real time), this new instrument produces single video frames which have superior resolution and contrast. This new real-time slit scanning confocal microscope produces en face, high contrast, high resolution, images of the wing cells, epithelial basal cells, corneal innervation, nuclei of stromal keratocytes, and the cell bodies of the stromal keratocytes in the posterior stromal region, and thus demonstrates its unique real-time imaging features. This real-time confocal microscope is based on a modular building block principle. This new microscope is equipped with water immersion microscope objectives which do not applanate the cornea; a polymer gel is used to optically couple the tip of the microscope objective to the eye.