Structural analysis of cataract incision construction.

This report examines the structural components of incision construction for cataract surgery so the causes of corneal instability and astigmatism can be understood. Changing the shape of the external incision, from limbus-parallel to linear to curved away from the limbus, results in a more stable external incision. The internal entry incision is more directly associated with corneal instability, however, and its construction and closure are crucial. Corneal stability improves as the closure changes from radial to horizontal to corneal valve autoclosure. Hyphema rates also improve with this progression because blood is directed into the anterior chamber with posterior incision closure, but out of the eye with anterior corneal valve closure.