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Change in choroidal nevi during a 5-year follow-up study: the Beijing Eye Study

Background To determine the risk of growth of presumed choroidal nevi in the adult Chinese population in Greater Beijing. Methods The Beijing Eye Study is a population-based study that was performed in 2001 and in 2006. Of 126 subjects with presumed choroidal nevi detected in 2001, 75 (60%) subjects returned for the follow-up examination and had readable fundus photographs available. To assess any change in size or shape of the nevi, we used flicker comparison of the fundus photographs. Results An enlargement of the presumed choroidal nevi was detected in four eyes (5.3±22.6% (mean±SD); 95% CI 0.1 to 10.5%) during the 5-year follow-up. In another four eyes (5.3±22.6%; 95% CI 0.1 to 10.5%), drusen of the retinal pigment epithelium overlying the nevi increased in size. None of the nevi regressed in size or showed clinical signs indicating a malignant transformation. The ages of the four participants with an increase in the nevus size were 43, 45, 46 and 56 years at baseline; best corrected visual acuity was 1.0 and frequency doubling perimetry results were normal. Conclusions Only a small percentage of adult Chinese participants aged ≥40 years showed an enlargement of presumed choroidal nevi during a follow-up period of 5 years. Taking into consideration that most of the study participants were already past the age of highest risk of developing a uveal melanoma in Chinese people, the results suggest a low risk of growth of choroidal nevi into malignant choroidal melanomas in Chinese people.