ABSTRACT
Polymorphic light eruption (PMLE) is very common worldwide, affecting some 20% of southern Scandinavians, 10%–15% of northern Americans and southern British, and 5% of southern Australians (Pao et al. 1994), but almost no equatorial Singaporeans. Its prevalence therefore decreases steadily with decreasing latitude, although this has been challenged in a later study, but purely of indoor workers with no regular sun exposure (Rhodes et al. 2010).
