Abstract
Purpose: :
The structure of collagen lamellae in the anterior stroma of the human cornea is thought to be an important determinant of corneal rigidity. We evaluated the three-dimensional structure of such collagen lamellae in normal human corneas.
Methods: :
The anterior portion of 27 normal human corneas was obtained from donor tissue for DSAEK surgery. Approximately 3-mm square blocks of the central cornea were examined by second harmonic generation (SHG) imaging microscopy. Each cornea was scanned from the surface of Bowman’s layer to a depth of 150 µm, and SHG forward signals were collected. The angles of collagen lamellae immediately below to a depth of 30 µm below Bowman’s layer (sutural lamellae) as well as of those at a depth of 50 or 100 µm were measured. The density and width of the sutural lamellae were also evaluated.
Results: :
The collagen lamellae in the anterior stroma were evenly distributed and randomly oriented. The angle of the sutural lamellae relative to Bowman’s layer was 19.08 ± 4.34 degrees (mean ±SD; range, 8.91 to 29.91). The angles of collagen lamellae at depths of 50 or 100 µm were 9.01 ± 2.91 (range, 3.46 to 18.25) and 7.04 ± 0.97 (range, 2.56 to 13.66) degrees, respectively. The average density of the sutural lamellae was 990.5 ± 364.1/mm2, and the width of the sutural lamellae was 12.6 ± 4.9 and 6.7 ± 2.8 µm in the region immediately beneath and 30µm below Bowman’s layer, respectively.
Conclusions: :
Collagen lamellae in the anterior stroma of the normal human cornea are interwoven in three dimensions and adhere densely to Bowman’s layer. This structure may contribute to the rigidity and curvature of the anterior portion of the cornea.
Keywords: cornea: stroma and keratocytes • extracellular matrix • anatomy