Corneal eccentricity and related factors in Chinese children and adolescents with astigmatism.

OBJECTIVE

To quantify the distribution of anterior corneal eccentricity (e value) and identify associated factors in Chinese children and adolescents with astigmatism.

METHODS

Corneal topography data obtained using the Medmont E300 were retrieved from 961 participants aged 3 to 18 years, with corneal astigmatism (ΔK) ≥ 2.00 D. Data analysis included anterior corneal e values along both flat and steep meridians at 1-10 mm chord lengths, as well as the device-reported mean e values for the flat and steep meridians (9.35 mm chord dimater); anterior corneal keratometry readings (flat/steep K); ΔK; and refractive error. Demographic factors, including age and sex, were also analyzed.

RESULTS

This study included 961 right eyes (mean age: 7.9 ± 2.9 years; 56% male). The mean e values were 0.73 ± 0.10 for the flat meridian and 0.51 ± 0.21 for the steep meridian. Along the flat meridian, e values decreased and stabilized with increasing chord length, while along the steep meridian, a U-shaped trend was observed. The mean flat e was correlated with the flat K (β = -0.013, P < 0.001) and ΔK values (β = 0.037, P < 0.001), whereas the mean steep e was only associated with sex (β = -0.043, P = 0.001) in multivariate analyses.

CONCLUSION

In Chinese children and adolescents with moderate to high corneal astigmatism, the anterior cornea demonstrates aspheric characteristics with distinct meridional asymmetry. The flat e value may was associated with corneal curvature (flat K and ΔK values), whereas the steep e value was not associated with these parameters.