A total of 25 patients (25 eyes; 14 males and 11 females; age, 1 month to 6 years [2.49 ± 1.81 years]) were enrolled in this study. The average AL and ACD of the right eye were 20.44 ± 1.66 mm and 2.78 ± 0.36 mm, respectively. AL was significantly correlated with age (Pearson's
r = 0.746,
P < 0.001) and ACD (
r = 0.659,
P < 0.001). AL and age were closely correlated by a logarithmic calculation (
r = 0.894). A scatterplot of AL and age is shown in
Figure 3A. ACD and age were closely correlated by a logarithmic calculation (
r = 0.567). A scatterplot of ACD and age is shown in
Figure 3B.
The average SER was 0.24 ± 1.04 D (n = 22). SER was significantly correlated with age (r = −0.435, P = 0.042), and marginally correlated with AL (r = −0.419, P = 0.051).
The average crystalline lens dimensions (mm) were as follows:
D, 7.39 ± 1.03;
T, 3.75 ± 0.41;
Ta, 1.86 ± 0.19; and
Tp, 1.94 ± 0.22. The equatorial lens diameter (
D) was significantly correlated with age (
r = 0.542,
P = 0.004), AL (
r = 0.799,
P < 0.001), ACD (
r = 0.398,
P = 0.048),
T (
r = 0.401,
P = 0.046), anterior
R (
r = 0.799,
P < 0.001), and posterior
R (
r = −0.739,
P < 0.001).
Ta was significantly correlated with
Tp (
r = 0.917,
P < 0.001), and SER with posterior
R (
r = 0.445,
P = 0.037,
n = 22). A scatterplot of the crystalline lens dimensions and age is shown in
Figure 4.
The average R and Q values of the anterior lens surface were 6.21 ± 1.74 mm and (4.60 × 10−4) ± (9.21 × 10−5), respectively. The average R and Q values of the posterior lens surface were −4.81 ± 1.07 mm and (2.49 × 10−4) ± (1.63 × 10−4), respectively. Therefore, the anterior and posterior lens surfaces within the central 120° zone were almost spherical. The mean RMS errors (mm) of the anterior and posterior fit were (4.68 × 10−5) ± (4.39 × 10−5) and (3.62 × 10−5) ± (2.60 × 10−5), respectively.
The first principal component (PC1) of the crystalline lens explained 89.15% of the total variance in lens shape, and the PC1 of the eyeball explained 74.23% of the total variance in eyeball shape. The PC1 of the crystalline lens was significantly correlated with age (r = 0.648, P < 0.001), AL (r = 0.847, P < 0.001), ACD (r = 0.649, P < 0.001), D (r = 0.661, P < 0.001), anterior R (r = 0.600, P = 0.001), and posterior R (r = −0.707, P < 0.001). The PC1 of the eyeball was significantly correlated with age (r = −0.549, P = 0.004), AL (r = −0.508, P = 0.009), ACD (r = −0.406, P = 0.043), D (r = −0.510, P = 0.008), and posterior R (r = 0.519, P = 0.007). The PC1 of the crystalline lens was also significantly correlated with the PC1 of the eyeball (r = −0.469, P = 0.001).
The correlation between the crystalline lens shape and other elements is shown in
Table 1. A scatterplot of age and the PC1 of the crystalline lens is shown in
Figure 5A.
Figure 5B shows the changes in shape variations within the value range of −2SD to 2SD for the PC1 of crystalline lens shape. A model of the average eye calculated on the basis of correlations between age and the principal component of the total variance in shape is shown in
Figure 5C. Multiple linear regression analysis revealed a coefficient of determination of 0.754, in which AL was a dependent variable. Only the PC1 of the crystalline lens was associated with AL (
Table 2). The scatterplots of the anterior and posterior crystalline lens curvatures (
R) and age, AL, the PC1 of the eyeball, and SER are shown in
Figure 6.