Variations in the clinical characteristics of geographic atrophy among Caucasians, Japanese Americans in Hawaii, and Japanese in Japan.

PURPOSE: To compare clinical characteristics of geographic atrophy (GA) among Caucasians in Hawaii (C-A), Japanese Americans in Hawaii (J-A), and Japanese in Japan (J-J).

DESIGN

Retrospective study.

METHODS

Consecutive patients with GA were recruited from single institutions in Hawaii and Japan, and GA areas within 6 × 6 mm² OCT scan area were measured on near-infrared images obtained at the latest visit. Ethnic differences in GA-related characteristics were assessed using mixed-effects models adjusted for age and sex. All values are means.

RESULTS

A total of 125 eyes from 91 patients were included: 51 eyes of 36 C-A (58% men), 36 eyes of 26 J-A (35% men), and 38 eyes of 29 J-J (69% men). Bilateral GA was more frequent in C-A (72%) than in J-J (34%, P < 0.01), while J-A (50%) did not differ from either group. The number of GA foci was greater in C-A (2.8) than in J-A (1.9, P < 0.05) and J-J (1.5, P < 0.01). GA area was significantly larger in C-A (10.3 mm²) than in J-J (6.0mm², P < 0.05), with J-A (8.8mm²) intermediate. Subfoveal choroidal thickness (SFCT) was thinner in C-A (83.3 µm) than in J-A (140.8 µm, P < 0.001) and J-J (165.3 µm, P < 0.0001).

CONCLUSIONS

The number of GA foci and SFCT differed between J-J and C-A as well as between J-A and C-A, suggesting genetic differences. In contrast, significant differences in GA area and bilaterality were observed only between J-J and C-A. The intermediate values in J-A may reflect environmental influences. Further studies are warranted.