Human ocular aging and ambient temperature.
A survey of the literature on the incidence of the age of onset of presbyopia in various parts of the world reveals a great deal of variation. At first sight this appears to correlate with geographical latitude, but statistical and epidemiological evidence rules this out in favour of ambient temperature. Indirect evidence suggests that the crystalline lens is located sufficiently near to the surface of the body for this to be a likely explanation.
D000328:Adult; D000375:Aging; D001838:Bolivia; D006801:Humans; D008875:Middle Aged; D011305:Presbyopia / Q000453:epidemiology*; D013696:Temperature