Cell Production and Migration in the Epithelial Layer of the Lens

The epithelial layer of the lens has been implicated in the pathogenesis of several types of cataract.1These types, which are progressive, slow to develop, and usually nonreversible, include various radiation cataracts such as those caused by ultraviolet, infrared, x-ray, γ-ray, neutron, β-ray, and radiomimetic agents such as busulfan (Myleran).* In a number of animal experiments where the germinative zone of the lens epithelium was selectively irradiated a slow forming opacity was found, whereas selective irradiation in other areas of the lens required much larger doses to produce the same effect.2-4These results give strong support to the idea that the lens epithelial cells, especially those cells of the proliferative zone, are directly involved in the developing opacity. The sequence of postulated events leading to the formation of radiation cataracts as first suggested by Rohrschneider2and outlined in a book by Duke-Elder5are as follows: "The