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Corneal parameters of six- to 12-year-old Chinese children
Ka Yin Chan1, Sin Wan Cheung, Pauline Cho
1School of Optometry, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong SAR, China. so.dede@polyu.edu.hk
Insights
This study found that Chinese children
Area of Science:
- Ophthalmology and optometry, focusing on pediatric eye health and refractive error development.
Background:
- Myopia (nearsightedness) is a growing concern in children, with corneal shape playing a role in refractive error.
- Understanding corneal parameters in pediatric populations is crucial for myopia management and predicting refractive development.
- Limited data exists on specific corneal characteristics of myopic Chinese children.
Purpose of the Study:
- To determine corneal parameters in low to moderate myopic Chinese children.
- To investigate sex-based differences in corneal parameters among these children.
Main Methods:
- Corneal parameters were analyzed from 217 Chinese children (ages 6-12) with low to moderate myopia.
- Data was collected using the Medmont E300 topographer, measuring simulated K (Sim K), asphericity (Q), and horizontal visible iris diameter (HVID).
- Subjects included 112 males and 105 females, with data retrieved from prior myopia and astigmatism studies (2008-2009).
Main Results:
- Corneas exhibited a prolate elliptical shape, with greater peripheral flattening along the flat meridian.
- Male subjects showed significantly larger HVID (11.3 mm vs. 11.1 mm) and flatter corneas (Sim K: 7.91 mm flat, 7.65 mm steep) compared to females (11.1 mm, 7.79 mm flat, 7.53 mm steep).
- No significant difference in corneal asphericity (Q) was found between sexes.
Conclusions:
- Chinese children's corneas demonstrate a greater peripheral flattening rate than Caucasian children.
- Male Chinese children tend to have larger HVID and flatter corneas than their female counterparts.
- These findings contribute to understanding ethnic and sex-specific corneal variations in myopic children.
Purpose:
The aim was to determine the corneal parameters in low to moderate myopic Chinese children and to investigate the differences in these corneal parameters between male and female subjects.
Methods:
Refractive errors and corneal parameters were retrieved from subjects who had participated in studies on myopia and astigmatism in 2008 and 2009. Corneal parameters including simulated K (Sim K) and asphericity (Q) at 9.0 mm chord and horizontal visible iris diameter (HVID) were determined for 217 children (112 males and 105 females aged from six to 12 years) using the Medmont E300 topographer.
Results:
The Q of the corneas was -0.44 ± 0.12 along the flat meridian and -0.22 (-0.70 to 0.63) along the steep meridian. The HVID and Sim K of male subjects were larger and flatter than female subjects. The mean HVID of male and female subjects was 11.3 ± 0.3 mm and 11.1 ± 0.30 mm, respectively. The mean Sim K value in male and female subjects was 7.91 ± 0.24 mm and 7.79 ± 0.21 mm, respectively, along the flat meridian, and was 7.65 ± 0.26 mm and 7.53 ± 0.24 mm, respectively, along the steep meridian.
Conclusions:
All corneas were prolate elliptical in shape along the flat meridian and the peripheral flattening rate was found to be greater along the flat meridian. A greater flattening rate was observed in the corneas of Chinese children when compared to that of Caucasian children. The Q between male and female subjects was not significantly different. Male subjects tended to have larger HVID and flatter corneas than female subjects.
