Prevalence of pinguecula in Greenland and in Copenhagen, and its relation to pterygium and spheroid degeneration.

The prevalence of pinguecula has been studied by slit lamp examination of 659 Eskimos in South Greenland and 810 Caucasians in Copenhagen. The overall prevalence was found to be 56 per cent in Greenland against 41 per cent in Copenhagen (P less than 0.001) and to rise with increasing age, though with a fall after the age of 60 among Greenland women. Pingueculae (measured by their vertical height) are largest among Greenlanders, and larger in males than in females. They increase in size with increasing age. They are generally located nasally in Greenlanders and temporally in Copenhageners. The prevalence of pinguecula in almost 1 1/2 times higher among Greenlanders than among Copenhageners, while that of spheroid degeneration and that of pterygium are 3 times and slightly over 10 times higher respectively. The incidence of pinguecula and spheroid degeneration are correlated per site and per subject in the two geographically different series. Pterygium is not correlated with regard to site, this being always located nasally. Pterygium practically never harbours spheroid degeneration, neither in its body nor in its head (81 pterygia). Pinguecula and pterygium are therefore to be regarded as two different disorders, while spheroid degeneration is related to pinguecula.