Pigmentation of iris, hair associated with retinal pigment abnormalities

Iris and hair pigmentation may be related to the incidence of some signs of age-related maculopathy, a population-based study suggests.

People with brown eyes were more likely to develop indistinct drusen than people with blue eyes, analysis of data from the Beaver Dam Eye Study showed. The data also showed that people with brown eyes were less likely to develop depigmentation of the retinal pigment epithelium.

Sandra Tomany, MS, Ronald Klein, MD and Barbara Klein, MD, of the University of Wisconsin Medical School analyzed 10-year data on 2,764 participants in the Beaver Dam Eye Study to assess relationships between hair color, iris color and skin and sun sensitivity and the incidence of age-related maculopathy (ARM). Data on these characteristics were gathered during baseline examinations.

Early ARM was defined by the presence of either soft indistinct drusen or the presence of any type of drusen associated with retinal pigment epithelium depigmentation or increased retinal pigment.

Late ARM developed in 72 participants over the 10 years of the study. Brown-eyed participants were more likely than blue-eyed participants to have incident soft indistinct drusen. People with brown and green eyes were less likely than were people with blue eyes to develop increased retinal pigment epithelium depigmentation at the 10-year follow-up. No association was found between iris color and the incidence of late ARM.

The results of this study contrast with an earlier publication from the Blue Mountain Eye Study, the Beaver Dam authors note in the August issue of Ophthalmology. That Australian population-based study found that people with blue eyes had a significantly higher incidence of early age-related maculopathy than those with darker eyes.

“The reasons for the inconsistent relationship between iris color and the 10-year incidence of lesions associated with early ARM found in our study are unknown,” reported Ms. Tomany and colleagues.

Participants younger than 65 had a significantly lower 10-year incidence of retinal pigment epithelium depigmentation than people with blue eyes; once participants were over the age of 65, a significant difference was not found.

“Another possible explanation for the increased risk of incident soft indistinct drusen found in brown-eyed participants compared with blue-eyed participants in our study is that it results from drusen being easier to detect in darkly pigmented fundi than in lighter-pigmented fundi,” the authors noted.