[Preliminary clinical observation of ocular biological parameters in transfusion-dependent β-thalassemia children]

Objective: To observe the characteristics of ocular biological parameters in children with transfusion-dependent β-thalassemia (TDT) and the effect of iron chelator treatment on them. Methods: This was a cross-sectional study. Thirty-two children with TDT (TDT group) and 64 healthy children (control group) who were treated in the Affiliated Hospital of Guangdong Medical University from October 2022 to June 2023 were included. There were 17 males and 15 females in the TDT group, with an age of (10.32±3.58) years; and 34 males and 30 females in the control group, with an age of (10.70±3.23) years. The children with TDT were divided into TDT1 group (using a single iron chelator) and TDT2 group (using two iron chelators in combination) according to the treatment situation of blood transfusion combined with iron chelator. The growth and development indicators such as height, weight and BMI of the children were recorded; the axial length (AL), anterior chamber depth (ACD), lens thickness (LT), central corneal thickness (CCT), corneal horizontal diameter (WTW), and the mean corneal curvature (Km) was calculated; the average size (AVG) of corneal endothelial cells and corneal endothelial cell density (CD) were measured using the corneal endothelium cytometer SP-3000P. to integer values; the blood transfusion time, serum ferritin before and after blood transfusion, the Results: The height, weight and BMI of the TDT group were all smaller than those of the control group (all P<0.001). The AL of the TDT group was (23.21±0.98) mm, shorter than that of the control group (24.01±1.16) mm; the ACD was (3.49±0.24) mm, shallower than that of the control group (3.63±0.25) mm; the LT was (3.52±0.18) mm, thicker than that of the control group (3.39±0.16) mm; The Km value (44.12±1.59) D is higher than that of the control group (42.93±1.34) D; the CD was (3 035.71±312.59) cells/mm², smaller than that of the control group (3 260.46±248.11) cells/mm² (all P<0.05). In the TDT group, AL and ACD were positively correlated with height (r=0.497,0.454;both P<0.05), and LT was negatively correlated with height (r=-0.400, P<0.05). The age of the TDT2 group was greater than that of the TDT1 group, the LT was smaller than that of the TDT1 group (P>0.05), and the CD was smaller than that of the TDT1 group (P<0.05). Conclusions: The growth and development of children with TDT are retarded, manifested as short axial length, shallow anterior chamber, thickened lens, higher mean corneal curvature and decreased corneal endothelial cell density. The use of iron chelators may cause corneal changes such as decreased corneal endothelial cell density.