Choroidal Nevi in Adult Chinese

Abstract

tains Eye Study. 4 The present study included 8447 (95.1%) eyes of 4277 (96.4%) participants, whereas the photographs of 431 (4.9%) eyes were lost or could not be assessed due to opacities of the optic media or poor photographs. The prevalence rate of choroidal nevi was 126 of 4277 (2.9%0.26% [mean standard error]) per subject or 1.5%0.13% per eye. In univariate analysis, the prevalence of choroidal nevi was significantly higher in men (3.9%0.45%) than in women (2.2%0.30%) and higher in rural areas (3.8%0.44%) than in urban areas (2.3%0.31%) (Tables 1, 2 [available at http://aaojournal.org]). It was not significantly associated with age (P 0.56). In binary logistic regression analysis, only male gender (P 0.02; odds ratio, 1.69; 95% confidence interval, 1.09‐2.70) was significantly associated with the prevalence of choroidal nevi. The mean largest diameter of the nevi was 1.480.74 mm (range, 0.51‐3.46), and the mean area of the nevi measured 1.751.88 mm 2 (range, 0.17‐8.82). As for the frequency, size of the choroidal nevi was not significantly associated with overlying drusen (P 0.15), position relative to macula (P 0.55), quadrant location (P 0.61), position relative to optic disc (P 0.93), gender (P 0.06), age (P 0.06), rural versus urban area (P 0.136), habit of smoking (P 0.75), and habit of alcohol use (P 0.90). Seventeen (13.1%) nevi had drusen overlying the nevus. Fifty-two (40%) were located in the superior temporal quadrant (relative to the optic disc), 45 (34.6%) were located in the inferior temporal quadrant, 23 (17.7%) were located in the inferior nasal quadrant, and 10 (7.7%) were located in the superior nasal quadrant. The posterior margin of 84 (64.6%) nevi were within 2 disc diameters of the optic disc, including 4 nevi touching the optic disc border, and 46 (35.4%) nevi were located more distant than 2 disc diameters from the optic disc border. Twenty-one (16.2%) nevi involved the macula area, defined as a region of 6 mm diameter and centered on the fovea. The results suggest that the prevalence of choroidal nevi in adult Chinese may be lower than that in Caucasian populations, according to previous population-based studies such as the Blue Mountains Eye Study (6.5%). 4 One has to take into account, however, that ethnic differences in the background pigmentation of the fundus may have influenced the ophthalmoscopic detectability of choroidal nevi and thus may be one of the reasons for differences between studies of various ethnic groups. Interestingly, most population-based studies on the prevalence of choroidal nevi, including our study, did not find significant variations in the prevalence of choroidal nevi with age. Assuming that that finding was not due to the study designs by including only older age groups, one may speculate that choroidal nevi are formed early in life and may then remain essentially static, at least beyond an age of about 40 years. All nevi detected in the present study were small, without signs predictive of malignant transformation.