ABSTRACT
The cornea transmits almost all incident light to the interior of the eye, serving as the first optical component in the visual system of vertebrate organisms and simultaneously providing a tough physical barrier to the external environment. This unique combination of physical properties exemplifies the diversity of extracellular matrix function. The obvious corneal role in light transmittance and the accessibility of the cornea to observation and experimental manipulation has led to an extensive body of research focused on the structure and function of the corneal extracellular matrix and its individual molecular components. The fact that corneal scarring contributes significantly to blindness worldwide adds an important rationale for these investigations into matrix function. As might be expected, corneal extracellular matrix exhibits a number of specialized features. This is particularly true with respect to the corneal proteoglycans, which differ markedly from those of other interstitial connective tissues and include a unique class of molecules. This chapter summarizes the historical development of our knowledge of the corneal proteoglycans and reviews recent progress in the determination of the molecular structure and biological roles of these interesting molecules.
