Choroidal nevi in a white population: the Blue Mountains Eye Study.

OBJECTIVE To determine the prevalence, morphologic characteristics, associations, and frequency of features reported to predict growth of choroidal nevi in a large population-based sample. METHODS A total of 3654 subjects aged 49 to 97 years participating in the Blue Mountains Eye Study had a detailed eye examination, including photography of 6 standard retinal fields. Nevi were graded from photographs. RESULTS Nevi were present in 6.5% of the population (n = 232), and were distributed equally between eyes. There was a slight decrease in nevus prevalence with increasing age. Nevus prevalence was higher in women than men, but this difference was not statistically significant. The mean nevus diameter was 1.25 mm (SD, 0.72 mm; range, 0.5 to >4.5 mm). Eighty-seven percent of nevi were blue gray and 6% had a hypomelanotic or amelanotic appearance. There were no significant associations between nevi and iris or skin color or sun-induced skin damage, but nevi were significantly less frequent in persons with blond hair. No nevus associations were found with visual impairment, cataract, or glaucoma. Clearly visible drusen were seen on 42% of nevi and were larger and more centrally distributed as nevus size increased. Features previously identified as predicting nevus growth, such as serous elevation and orange or other pigment, were seen rarely. CONCLUSION Choroidal nevi in the general population are frequent, small, have few features that are commonly reported to indicate potential for growth, and rarely affect visual acuity.