Corneal and superficial conjunctival pigmentation in Eskimos, Mongols, and Caucasians

Pigmentation was noticed on or round the cornea in 44% of 257 Eskimos (East Greenland) and 25% of 189 Mongols (Japan), but no more than 4% of 795 Caucasians in Denmark. Superficial pigmentation on the bulbar conjunctiva was seen in 58% of Eskimos, 48% of Mongols and 10% of Caucasians. In Eskimos it is in most cases localized nasally (54%). In Caucasians the inferior and superior sites predominate (39% and 30%, respectively). The prevalence in both groups was found to rise with increasing age and to be significantly highest among men. Pigmentation of the cornea alone was most frequent among Mongols (22%). Then followed Eskimos (14%) and Caucasians (2%) in decreasing order. The pigmentation on or round the cornea is independent of iris colour in Caucasians, but is related to melanosis of the bulbar conjunctiva, the caruncle and the plica semilunaris.