An immunoelectron microscope study of the aged human lens capsule.

The distribution of types I-IV collagen and laminin was studied in seven aged human lens capsules using the immunogold EM technique on LR White embedded tissue. Samples were taken from the anterior, equatorial and posterior regions. Labelling for type II collagen was not observed. Type IV collagen was evenly distributed throughout the thickness of the capsule but was absent from the zonules. However, an unexpected finding was strong labelling for types I and III collagen, again evenly distributed throughout the capsule. The presence of type III collagen makes the lens capsule unique among ocular basement membranes. Laminin was present in linear densities, zonular lamellae and zonular fibres, suggesting that linear densities are an integral part of the zonular apparatus.