Natural and radiation-induced cataracts in man and mouse, and natural macular degeneration in man: proposed mechanisms

A unified theory of growth and age-dependent disorders is applied to the interpretation of epidemiological data for natural and radiation-induced cataracts and natural macular degeneration in man. Using the same unified theory, mechanisms are also proposed to explain the experimental evidence for natural and radiation-induced lenticular opacities in the lens of the mouse. Epidemiological and experimental data are strikingly consistent with the hypothesis that natural cataract formation is an autoaggressive process but the details of pathogenesis differ greatly between the two species. Radiation dose-response relations reflect these contrasts. Lenticular opacities in the nuclear-bomb survivors at Hiroshima and Nagasaki were probably induced by a 'single-track' mechanism. Radiation-induced generalised opacification in the lens of the mouse results from a 'multi-track' process. The pathogenesis of natural macular degeneration in man happens to have close parallels with that of natural opacification in the mouse. The authors discuss some implications of these inferences for the phenomenon of radiation-induced lethal disorders in man.