Posterior capsule opacification: experimental analyses.

The lenses of New Zealand White and Flemish Giant rabbits were removed using five techniques representative of the different clinical approaches to extracapsular cataract extraction currently employed. Posterior capsule opacification developed in all experimental animals within 6 weeks of the operation. None of the techniques reduced the incidence of the capsular opacification. Histological analyses including immunofluorescent and tritiated thymidine labelling were used to determine the nature of the cellular constitutents of the secondary membrane. The evidence indicates that the opacity is due not only to lens cells remaining after the operation but also consists of cells of nonlenticular origin. The data strongly implicate the anterior uvea as the source of those cells. Furthermore, the findings suggest that posterior capsule opacification is the product of a migration and a proliferation of both cell populations.