Pseudoexfoliation (PXF) has been considered to be a genetically-determined degeneration. The geographical variation seen in the distribution of PXF has been thought to support this. Australia Aborigines have been found to have a high prevalence of PXF, which occurs in over 16% of those over the age of 60 years. A series of 350 Aborigines was examined in detail to study the possible association of a number of personal and environmental factors with the presence of PXF. The condition occurred more commonly in older age groups, and it was three times more common in males than in females. A strong occupational association was also found; men who had worked as stockmen had a significantly higher rate of PXF than other groups. PXF occurred more commonly at lower latitudes and was seen more frequently with higher levels of global radiation. It is postulated that PXF may, in fact, be an environmental disorder caused by solar radiation. Possible pathogenetic mechanisms are discussed.