In vivo investigations of the corneal epithelium with the confocal Rostock Laser Scanning Microscope (RLSM)

Background: The confocal tandem scanning microscope was first used in 1985 by Lemp et al for in vitro and in 1990 by Cavanagh et al for in vivo investigation of human eyes. The aim of this study was to investigate the cells of the central and the peripheral portions of the corneal epithelium and to measure corneal epithelium thickness and the total thickness of the corneas of our volunteers with the new Rostock Laser Scanning Microscope. Material and Methods: A Heidelberg Retina Tomograph (HRT II) was used in combination with a water contact microscope lens (Zeiss, x 63, 0.95), the Rostock cornea module (RCM) developed at our institute for the in vivo examination of the cornea. In this study, 92 eyes of 68 subjects between the ages of 15 and 88 years were examined. Results: At the superficial cell layer, the average cell density in the central cornea was 840 +/- 295 cells/mm(2), and in the periphery it was 833 +/- 223 cells/mm(2). At the wing cell layer, the average cell density rises to 5070 +/- 1150 cells/mm(2) in the central and to 5582 +/- 829 cells/mm(2) in the peripheral cornea. At the basal cell layer, the cell density rises further to 8996 +/- 1532 cells/mm(2) in the central and 10,139 +/- 1,479 cells/mm(2) in the peripheral corneal epithelium. The average corneal thickness in the central region was found to be 545 +/- 25 mu m, and 652 +/- 75 mu m in the periphery. The average epithelium thickness was determined centrally to be 54 +/- 7 mu m, and peripherally 61 +/- 5 mu m. Conclusions: The Rostock Scanning Laser Microscope offers a standardized. reproducible, safe, and fast diagnostic procedure for the evaluation of the corneal epithelium. This technology allows better image quality compared with confocal-slit scanning microscopes and produces a precise depth measurement.