Abstract
Purpose: :
To compare the distribution and the preferred fibril orientation of collagen in the porcine and human cornea.
Methods: :
One human cornea and one porcine cornea were excised with scleral rim from intact globes within 24 hours post–mortem. Wide angle x–ray scattering (WAXS) patterns were obtained across a 2–D grid at 1–mm intervals using a computer–operated translation stage on Station 14.1 at the Daresbury Synchrotron Radiation Source, UK. Each WAXS pattern was analyzed to produce quantitative information regarding the relative amount of collagen (aligned and isotropic) and the preferred orientation of preferentially aligned collagen at a known corneal location. The data were then combined to yield maps showing the variation of these properties across the cornea and limbus.
Results: :
A similar collagen distribution is seen in porcine and human corneas, however the preferred orientation of collagen differs between the two species. In contrast to the human cornea, which exhibits a preferred orthogonal orientation of collagen in the superior–inferior and nasal–temporal directions, a uniaxial preferred orientation of collagen is observed in the porcine cornea.
Conclusions: :
Based on the observed differences in collagen orientation between the human and porcine cornea, one may expect a difference in the structural response of the two tissues to surgery.
Keywords: cornea: basic science • comparative anatomy • refractive surgery: comparative studies