Trabecular meshwork and uveoscleral outflow models.

PURPOSE: To describe current laboratory models used to study aqueous outflow. Because development of primary open angle glaucoma (POAG) is rare in animals, no animal model of POAG is available for laboratory study on the pathogenesis of this condition. This review will discuss the alternative models used in the laboratory to study aqueous outflow.

METHODS: This is a brief review of published techniques, with commentary upon advantages and limitations of each.

RESULTS: Whole eyes and anterior segments are useful in assessing aqueous outflow resistance and anatomical changes in the meshwork. They have a limited duration of viability. Cell cultures are less expensive, easier to obtain, provide more cells than in intact meshwork, and are excellent in studying cellular physiology. The artificial environment of cell culture, however, including the plastic dish or artificial substrate and also the requirement of serum supplements, may limit applicability. Modern understanding of cells, their interaction with the extracellular matrix, and sensitivity to the composition of culture media suggest that these laboratory models should be updated to more closely mimic the in vivo situation.

CONCLUSION: Outflow models are a useful beginning in the study of cellular physiology, cell-extracellular matrix interactions, and reactions of the whole meshwork. All have limitations, however; the development of an animal model of human POAG would be an ideal solution to many of the current limitations.