AIM:To measure the superficial capillary plexus(SCP)vessel density(VD), deep capillary plexus(DCP)VD, and the area, circumference, and roundness index of the foveal avascular zone(FAZ)in healthy individuals of four ethnic groups, namely, Uyghur, Han, Kazakh, and Hui by optical coherence tomography angiography(OCTA), and to investigate the differences of blood flow parameters in macular area of healthy individuals among different ethnic groups in China.

METHODS: A total of 80 cases(80 eyes)of healthy subjects if each of the four ethnic groups who went to the Eye Center of the Friendship Hospital of Ili Kazak autonomous Prefecture from December 2022 to March 2023 and met the criteria were selected for the study, with 320 eyes totally. The patients were grouped and numbered according to their ethnicity, and the spherical equivalent and axial length were obtained by using an autorefractor and IOL Master. The blood flow images of the macular area in the range of 3 mm×3 mm were obtained by using a DRI Triton OCT detector, and the images were analyzed by using the built-in IMAGENET6 software to obtain the blood flow parameters. Furthermore, the differences in the blood flow parameters between different ethnic groups as well as the effects of gender, age, and axial length on macular blood flow parameters of different ethnic groups were compared.

RESULTS:There were no statistically significant differences in gender, age, axial length, diopter, and image quality(IQ)among the four groups of subjects(all P>0.05). Ethnic differences: in SCP, Uyghur inferior VD is higher than Kazakh, Hui inferior VD is higher than Han and Kazakh, Han and Hui nasal VD is higher than Uyghur, Kazakh foveal VD is higher than Han and Hui, Kazakh FAZ area is smaller than the other 3 ethnic groups, Han and Hui FAZ perimeter is larger than Kazakh, and Hui FAZ circularity index is lower than the other 3 ethnic groups; in DCP, Uyghur foveal VD is higher than Han and Hui, Kazakh foveal VD is higher than Han and Hui, Kazakh FAZ area and perimeter are smaller than the other 3 ethnic groups and Kazakh FAZ circularity index is higher than the other 3 ethnic groups(all P<0.05). Sex differences: in SCP, FAZ area and perimeter of Han females were larger than those of males, and FAZ circularity index of Hui females was higher than that of males(all P<0.05); in DCP, parafoveal VD and whole VD in females of all four ethnic groups were higher than those of males(all P<0.05). Age correlation: in SCP, age was negatively correlated with the FAZ circularity index of Kazakh; in DCP, age was negatively correlated with the parafoveal and the whole VD of Han, Kazakh, and Hui(all P<0.05). Axial length correlation: in SCP, the axial length was negatively correlated with Kazakh and Hui foveal VD, Hui parafoveal VD, Uyghur, Kazakh and Hui whole VD, and positively correlated with Kazakh FAZ area and perimeter; in DCP, the axial length was negatively correlated with Uyghur, Kazakh, Hui foveal VD, Hui whole VD, and positively correlated with Kazakh and Hui FAZ area and perimeter(all P<0.05).

CONCLUSION:There were differences in macular blood flow parameters among the Uyghur, Han, Kazakh, and Hui populations, with the area and perimeter of the FAZ of the Kazakh significantly smaller than those of the other three ethnic groups. Gender, age, and axial length are also related to macular blood flow parameters.