| Objective: To observe the changes of choriocapillary blood flow density in macular region and perioptic disc in adolescents with emmetropia and myopia,and to analyze its correlation with equivalent spherical diopter(spherical equivalent degree,SER),macular subfoveal choroidal thickness(subfoveal choroidal thickness,SFCT)and axial length(axial length,AL).Methods: cross-sectional study.A total of 150 eyes of 150 adolescents who met the inclusion criteria in the Ophthalmology Center of Qingdao Municipal Hospital from 2022.1 to 2022.9 were collected and divided into four groups: emmetropia group,low myopia group,moderate myopia group and high myopia group according to different equivalent spherical diopters.There were 38 cases(eyes)in emmetropia group,38 cases(eyes)in low myopia group,38 cases(eyes)in moderate myopia group and 36 cases(eyes)in high myopia group.The choriocapillary layer images of macular area and perioptic disc were obtained by OCTA,and the choroidal capillary blood flow density was measured by Image J software.The equivalent spherical diopter was obtained by objective optometry and subjective optometry after mydriasis.The subfoveal choroidal thickness was obtained by depth enhanced imaging(enhanced depth imaging optical coherence tomography,EDI-OCT)mode of coherent optical tomography,and the length of eye axis was measured by optical biometric instrument.The data of all subjects were processed by SPSS25.0 statistical software: the number of cases of counting data was described;the gender was described by chi-square test;continuous variables were described by mean ±standard deviation;the analysis of variance was consistent with normal distribution and variance was uniformly used by single factor and multi-level;nonparametric rank sum(Kruskal-Wallis H)test was used for non-normal distribution or variance discrepancy.The correlation analysis was Spearman correlation analysis,and the difference was statistically significant.Results: the age,SER,AL,SFCT,macular choroidal capillary blood flow density and perioptic disc choroidal capillary blood flow density of subjects in each group were 23.847,140.092,95.979,53.187,60.627 and34.450,respectively,but there was no significant difference between male and female.In pairwise comparison,the choriocapillary blood flow density in macular region in emmetropia group,low myopia group and moderate myopia group was significantly higher than that in high myopia group(P <0.001,P < 0.001),and the choriocapillary blood flow density around optic disc in emmetropia group,low myopia group and moderate myopia group was significantly higher than that in high myopia group(P < 0.001,P <0.01,P < 0.01).There was no significant difference in choriocapillary blood flow density between low myopia group and moderate myopia group in macular area and around optic disc(P < 0.01).The results of correlation analysis showed that the correlation coefficient between choriocapillary blood flow density and AGE,SER,AL,SFCT in macular area was higher than that around optic disc.The correlation coefficient between choroidal capillary blood flow density and choroidal capillary blood flow density in macular area was higher than that around optic disc.The choroidal blood flow density in the macular area decreased faster than that in the optic disc area(K1 > K2 ~ K1 ~ 2.892 ~ 2.038).The blood flow density of choroid capillaries in II macular region and perioptic disc were negatively correlated with AL(r = 0.490,P < 0.001,r = 0.316,P < 0.001),and negatively correlated with age(r = 0.237,P < 0.004).The blood flow density of choroid capillaries in macular area(r = 0.590,P < 0.001)and around the optic disc(r = 0.435,P < 0.001)and around the optic disc(r =0.435,P < 0.001)were positively correlated with SER,SFCT.Conclusion:1.With the increase of myopia,the choroidal capillary blood flow density in macular area and around optic disc decreased,and the choroidal capillary blood flow density in macular region decreased more rapidly.2.In the adolescent macular area,the choroidal capillary blood flow density around the optic disc was highly correlated with the ocular axis length and the subfoveal choroidal thickness,negatively correlated with the ocular axis,and positively correlated with the subfoveal choroidal thickness. |
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