Circumcorneal annulus of collagen fibrils in the human limbus.

The excess of circumferential fibrils in the limbus, predicted from the sharp change of curvature in the surface of the eye at the limbus, appeared to take the form of a well-defined annulus. From a consideration of the mechanics of the system it seemed probable that the purpose of this annulus was to help maintain the correct curvature of the cornea. Before further research, it was hypothesized that some refractive problems associated with an incorrect curvature of the cornea may be related in part to abnormalities of this circumcorneal annulus.