OPTICAL SECTIONING OF THE CORNEA WITH A NEW CONFOCAL IN-VIVO SLIT-SCANNING VIDEOMICROSCOPE

Purpose: The purpose of this article is to introduce a newly developed confocal in vivo slit-scanning microscope for continuous recording an d real-time imaging of the various corneal subsegments of the patient' s eye with high microscopical resolution and adequate contrast. Method s: One-dimensional confocal slit-scanning videomicroscopy of the human cornea was performed with an instrument mainly consisting of a scanni ng module, an image-intensifier video camera, a Video monitor, and a s ynchronization unit for matching optical scan and video cycle with res pect to frequency and phase. Light intensity or fluorescence intensity profiles through the cornea could be obtained by microphotometric rec ording of part of the imaging light. An immersion contact technique us ing an isotonic tear replacement liquid with thixotropic properties av oids any mechanical contact between the front lens of the microscope o bjective and the corneal surface. Results: in normal human eyes, the c orneal micromorphology could be made visible with satisfactory lateral and axial resolution and with good contrast. The separately focussed sections of the cornea showed the endothelial cells, the superficial, intermediary, and basal cells of the epithelium, as well as stromal ke ratocytes and nerves. Even in eyes with significant corneal opacities resulting from corneal edema, the endothelial pathology could be image d with sufficient contrast. Conclusion: The in vivo slit-scanning vide omicroscopy offers real-time noninvasive and noncontact serial imaging of corneal subsegments with resolution and imaging contrast. Thus, an important step toward using confocal scanning microscopy for corneal diagnosis seems to be done.