[Iris heterochromia: variations in form, age changes, sex dimorphism].

On a sample of n = 25,346 individuals from Vienna (10,855 males, 14,491 females) the iris pigmentation has been typed by the author. In this sample 65 cases of different types of heterochromia were found. The frequency of the occurrence of the different types of this anomaly could be calculated for the first time. Neglecting age, sex, and type of heterochromia the total frequency amounts to 0.256 (males: 0.157; females: 0.37) %. The variants of heterochromia very from cases of total heterochromia to those of various size; in addition to it a number of special types could be observed. The localization of the heterochrome parts of the iris shows certain variations; mostly, however, it is seen in the lower half of the iris. The nasal part is concerned in only one case; the temporal region never. Thus, the partial heterochromia is characteristic by a marked dependency of its localization. The colour of heterochromia varies from 2 a-14 according to the Martin-Schultz standard set of coloured eyes. However, No. 9 (ca. 50%) and No. 7 (ca. 20%) were the most frequent colours. The age variations are considerable. 5/6 of all heterochromias were found between the age from 2-19 years. Finally, a marked sexual dimorphism was observed, as in females heterochromia is much more frequent than in males.