HETEROCHROMIA of the iris associated with iris coloboma has been described only once in the literature as a rare finding.1 Herein we describe and illustrate a series of 13 cases to emphasize its frequent occurrence and propose a possible explanation for the cause of the iris coloboma–iris heterochromia association.
As part of a detailed population study of congenital eye defects in Scotland, 75 children (aged 4-16 years) with iris colobomas were examined in detail. In 13 (17.3%) of these patients, there was a noticeable iris heterochromia (Figure 1), which is particularly striking in those cases where the unaffected eye is blue (Figure 2). In unilateral cases, the heterochromia is characterized by the darker iris being the one affected with the coloboma (Figure 3). In cases of bilateral iris coloboma with clinical microphthalmos and reduced corneal diameter (Table 1), the variation in iris color is inconsistent. A fundus coloboma (Figure 4) may be present, but not always.
Morrison DA, FitzPatrick DR, Fleck BW. Iris Coloboma With Iris Heterochromia. Arch Ophthalmol. 2000;118(11):1590-1591. doi:10.1001/archopht.118.11.1590