Corneal Power, Anterior Segment Length and Lens Power in 14-year-old Chinese Children: the Anyang Childhood Eye Study

Abstract

To analyze the components of young Chinese eyes with special attention to differences in corneal power, anterior segment length and lens power. Cycloplegic refractions and ocular biometry with LENSTAR were used to calculate lens power with Bennett’s method. Mean refraction and mean values for the ocular components of five different refractive groups were studied with ANOVA and post-hoc Scheffé tests. There were 1889 subjects included with full data of refraction and ocular components. As expected, mean axial length was significantly longer in myopic eyes compared to emmetropes. Girls had steeper corneas, more powerful lenses and shorter eyes than boys. Lens power was lower in boys and also lower in myopic eyes. Lens thickness was the same for both genders but was lower in myopic eyes. Although cornea was steeper in myopic eyes in the whole sample, this was a gender effect (more girls in the myopic group) as this difference disappeared when the analysis was split by gender. Anterior segment length was longer in myopic eyes. In conclusion, myopic eyes have lower lens power and longer anterior segment length, that partially compensate their longer axial length. When analyzed by gender, the corneal power is not greater in low and moderate myopic eyes.

Lens power in Iranian schoolchildren: a population-based study

“…Our study showed higher LP and in girls than boys (unstandardised regression coefficient: 0.016). This difference has also been reported by Iribarren et al .,3 Li et al 18 and Twelker et al 8. Nevertheless, it should be noted that this difference is not influenced by other ocular components because their effects were controlled in the regression model.…”

“…According to our findings, the highest and lowest LP was seen in hyperopic and myopic children, respectively; although Jones et al ,11 Li et al 18 and Iribarren et al 3 reported similar findings in children, Olsen19 reported a different finding in adults. Nonetheless, the LP decreased in myopic, hyperopic and emmetropic children with age.…”

Corneal curvature in young high myopic undergraduates in southern Nigeria

“…1,12,13 We found in our study that female students with high myopia had shorter mean average corneal curvature, similar to Li et al, but females without refractive errors had slightly higher mean average corneal curvature than males in another study. 13,14 A result similar to a study done by Iyamu and Osuobeni were they found that age and gender did not affect corneal curvature in emmetropes, however we only found a significant effect with gender on the corneal curvature of the young undergraduates with high myopia. 13 Our study is also in agreement with a previous study that there was no significant mean differences (P>0.05) between the various degrees of high myopia.…”

Intraocular pressure and myopia progression in Chinese children: the Anyang Childhood Eye Study

“…The significant difference in IOP between genders, the lower pressure found in both male and female hyperopes than in myopes (figure 1C), and the lower pressure found in eyes with lower myopic refractive error at baseline (figure 1D) are difficult to explain. Girls and hyperopes are known to have smaller anterior segments,11 so it is not clear why girls have higher pressure and hyperopes lower pressure. More research in this area is warranted.…”