The zonular insertion: a scanning electron microscopic study.

The zonular insertion on the human lens capsule has been studied with scanning electron microscopy. The whole insertional area is covered by a variety of 35 to 55 nm. fibrils, including those of the major inserting zonules, the meridional zonules, capsular surface fibrils, and a nonoriented fibrillar layer over the zonules. All appear to be zonular in type. The meridional zonules span the equator and are a form of insertion shared by the three levels of major zonules, probably helping to distribute their lateral pull. Surface rippling over the zonular insertion appears to result from greater contraction of the oriented fibers than of the nonoriented fibrils and superficial capsule. Surface meshwork fibrils attach to the capsule by becoming embedded in a granular capsular matrix 0.5 to 1 mu thick.