ObjectiveTo observe the correlation between retinal capillary density and retinal thickness in the macula and spherical equivalent (SE) in school-age children. MethodsA cross-sectional study. From May to December 2022, 182 school-age children who visited the ophthalmology department of the First Affiliated Hospital of Zhengzhou University were included . There were 95 males and 87 females. The age ranged from 6 to 12 years, and the spherical equivalent (SE) was +0.50 to －6.00 D. They were divided into three groups based on the SE of the right eyes: 54 eyes in emmetropia group (+0.50≤SE＜－0.50 D), 71 eyes in low myopia group (－0.50≤SE＜－3.00 D), and 57 eyes in moderate myopia group (－3.00≤SE≤－6.00 D). The macular area of 6 mm×6 mm was scanned using swept-source optical coherence tomography angiography and was divided into three concentric rings centered on the fovea, including the macular central fovea (0-1 mm diameter), inner ring (1-3 mm diameter) and outer ring (3-6 mm diameter). The retinal thickness and blood flow density of superficial vascular plexus (SVP) and deep vascular plexus (DVP) in different zones within 6 mm of the macular area were measured. The relationships between SE and SVP, DVP and retinal thickness in each ring region were investigated by univariate and multivariate linear regression analyses, smooth curve fitting, and threshold effects. ResultsThere were significant differences in the SVP (F=6.64, 26.06, 22.69) and DVP (F=7.97, 25.01, 5.09) of macular central fovea, inner ring and outer ring among the emmetropia, low myopia and moderate myopia groups (P＜0.05). Univariate linear regression analysis showed that the SVP (β=－0.56, －1.17, －0.79) and DVP (β=－1.03, －0.93, －0.45) of the three regions were positively correlated with SE (P＜0.05). After smooth curve fitting, threshold effect analysis and multivariate linear regression analysis, the SVP and DVP in the macular central fovea were linearly positively correlated with SE (β=－0.91, －1.40; P＜0.05), and SVP and DVP in the inner ring and outer ring showed an inverted U-shaped curve relationship with SE with the inflection (＜3.00 D). When the SE was less than ＜3.00 D, the SVP and DVP in the inner ring and outer ring were positively correlated with SE (P＜0.05). When the SE was higher than －3.00 D, except for the DVP in the inner ring region, the other parameters were negatively correlated with SE (P＜0.05). There were significant differences in retinal thickness of the inner ring and outer ring (F=5.47, 16.36; P＜0.05), and no significant difference in the macular central fovea among the emmetropia, low and moderate myopia groups (F=2.16, P＞0.05). By using univariate and multivariate linear regression analyses, the retinal thickness in the inner ring and outer ring were negatively correlated with SE (β =1.99, 3.05; P＜0.05). However, no correlation was found between retinal thickness and SE in the macular central fovea (β=－1.65, P＞0.05). ConclusionsIn school-age children with SE between +0.50 D and －6.00 D, the retinal capillaries density of the macular central fovea gradually increase, and increase first and then decrease in the inner ring and outer ring with increasing SE. The retinal thickness of inner ring and outer ring gradually decrease and not change significantly in the macular central fovea.
Objective To observe macular vascular density and structural characteristics in children with transfusion-dependent β-thalassemia (TDT). MethodsA retrospective clinical study. From October 2022 to December 2023, 29 TDT children (58 eyes) diagnosed and examined at the Department of Hematology, Affiliated Hospital of Guangdong Medical University were included in the TDT group, along with 29 age- and gender-matched healthy children (58 eyes) as the control group. All participants underwent optical coherence tomography and angiography. Measurements included central macular thickness (CMT), subretinal choroidal thickness (SFCT), choroidal thickness (ChT), choroidal vascularity index, blood flow density in the superficial capillary plexus (SCP), deep capillary plexus (DCP), choriocapillaris layer (CC), and choroidal layer of the macular region, as well as the foveal avascular zone (FAZ) area of the SCP and DCP. A generalized estimating equation was used to compare differences in the above parameters between the two groups. Pearson correlation analysis was employed to examine the relationships between fundus structural parameters, blood flow density, and blood indices. ResultsCompared with the control group, the TDT group showed significantly thinner CMT (χ2=6.044) and ChT at 3.0 mm nasal (χ2=4.451) and temporal (χ2=4.767) to the fovea (P＜0.05). The TDT group also demonstrated reduced blood flow density in the inferior DCP (χ2=5.254), whole CC (χ2=3.996), and superior CC (χ2=5.094), as well as enlarged FAZ area in DCP (χ2=4.286) (P＜0.05). Correlation analysis revealed a negative correlation between SFCT and disease duration (r=-0.357, P=0.006). ConclusionsIn children with TDT, CMT and ChT become thinner and the area of FAZ expands. The blood flow densities of DCP and CC in the macular area decreased.