Sex Differences in Rate of Axial Elongation and Ocular Biometrics in Elementary School Students

Figures & data

Table 1 Ocular Biometrics of Boys and Girls

Biometrics	Boys (50 Eyes)	Girls (52 Eyes)	P value
1st year ACD (mm)	3.71 ± 0.22 (3.25 to 4.17)	3.53 ± 0.25 (2.64 to 3.94)	0.001
1st year LT (mm)	3.53 ± 0.18 (3.18 to 4.00)	3.56 ± 0.19 (3.23 to 4.16)	0.55
1st year AL (mm)	23.69 ± 0.83 (21.87 to 25.80)	23.14 ± 0.90 (20.52 to 25.46)	0.001
2nd year AL (mm)	23.96 ± 0.91 (21.95 to 26.12)	23.39 ± 0.99 (20.73 to 26.01)	0.003
3rd year AL (mm)	24.23 ± 0.97 (22.03 to 26.34)	23.60 ± 1.06 (20.80 to 26.26)	0.002
First half AL elongation (mm)	0.27 ± 0.15 (0.04 to 0.60)	0.25 ± 0.17 (0.08 to 1.41)	0.34
Second half AL elongation (mm)	0.27 ± 0.16 (0.01 to 0.66)	0.21 ± 0.16 (−0.02 to 0.88)	0.032
TALE (mm)	0.54 ± 0.26 (0.16 to 1.11)	0.46 ± 0.31 (0.08 to 1.41)	0.09
GRC (mm)	0.00 ± 0.16 (−0.43 to 0.45)	−0.04 ± 0.14 (−0.37 to 0.35)	0.37

Abbreviations: AL, axial length; ACD, anterior chamber depth; LT, lens thickness; TALE, total axial length elongation; GRC, growth rate change.

Figure 1 Scatter plot of the first year ocular biometrics, viz., the anterior chamber depth (ACD), lens thickness (LT), axial length (AL), and total axial length elongation (TALE) (A–C), and growth rate change (GRC) (D–F) in boys (blue dots) and girls (red dots). In boys, the TALE was significantly larger in the eyes with myopic ocular biometrics such as a deeper ACD (r = 0.45, P = 0.001, (A), thinner LT (r = −0.46, P = 0.001, (B), and longer AL (r = 0.42, P = 0.002, (C) at the initial examination. In girls, the TALE was significantly larger in the eyes with myopic ocular biometric values such as a deeper ACD (r = 0.41, P = 0.002, (A), thinner LT (r = −0.44, P = 0.001, (B), and longer AL (r = 0.42, P = 0.002, (C) at the 1st year. The GRC accelerated significantly in the eyes of girls only with hyperopic ocular biometrics such as a shallower ACD (r = −0.32, P = 0.022, (D), thicker LT (r = 0.31, P = 0.027, (E), and shorter AL (r = −0.41, P = 0.003, (F) at the 1st year measurements. Similar tendencies were observed in boys (ACD, r = −0.09, P = 0.52, D; LT, r = 0.07, P = 0.65, E; AL, r = −0.27, P = 0.055, (F), but the differences were not significant.