Uneven swelling of the corneal stroma.

The surface V3 of the denuded corneal stroma was separated into the anterior and posterior segments; the swelling ratio of each was compared under zero pressure. In the rabbit, cat, and bovine corneas, the anterior segment was less hydrophilic than the posterior one, in both the central and peripheral regions. In the rabbit cornea, the swelling ratio of the posterior segment was significantly larger in the central region than in the peripheral. A fine glass capillary was implanted into the stroma as a landmark on the living eye. Corneal swelling was induced by means of irrigation with cold Ringer's solution. In vivo, under normal intraocular pressure, as in vitro, the anterior layers were less hydrophilic than the posterior. In order to clarify the relationship between uneven swelling and clouding of the stroma, successive observations of light scattering and simultaneous thickness measurements were made on the anterior and posterior layers of the enucleated eye at the various stages of swelling. An intense light scattering occurred with slight swelling in the anterior layers, while in the posterior layers, relatively slight scattering occurred with a high degree of swelling. This paradoxical finding leads to the supposition that the hydration of the stroma bears quite a different relation to light scattering in the respective layers. The principle that light scattering occurs in proportion to the degree of swelling cannot be applied to the other zone beyond the boundary between the anterior and posterior zones.