Mapping of normal corneal K-structures by in vivo laser confocal microscopy.

PURPOSE: To produce 2-dimensional reconstruction maps of normal human corneal fibrous structures beneath the Bowman layer (K-structures) by in vivo laser confocal microscopy and to show association of structures with the anterior corneal mosaic (ACM).
METHODS: Central corneal regions of 3 healthy volunteers were scanned. Acquired images of K-structures for each eye were arranged and mapped into a subconfluent montage. For each subject, electrical tracings of K-structures were superimposed on a slit-lamp photograph of the ACM produced by rubbing the eyelid.
RESULTS: A mean of 677 +/- 211 images of K-structures were obtained for each eye. Mean dimensions of the mapped areas were 5.88 +/- 0.50 (horizontal) and 3.51 +/- 1.37 mm (vertical). In all subjects, K-structures formed a netlike pattern (mean area, 0.082 +/- 0.051 mm), and electrical tracings had good concordance with the ACM.
CONCLUSIONS: This is the first study, to our knowledge, to elucidate the overall distribution of K-structures in normal human corneas. The netlike pattern of K-structures corresponded well with ACM pattern. These results support the hypothesis that the K-structures are the anterior collagen fiber bundles running at the posterior surface of the Bowman layer and thus are the structural basis for ACM formation.