Why carry out this study?

Accurate assessment of the range of normal corneal morphological parameters is crucial for the identification of many preclinical corneal diseases.

With the rapid development of technology for corneal refractive surgery, the effective prevention of postoperative corneal dilation and increased safety has become an important part of preoperative screening for individuals scheduled.

A defined normal reference range for an evaluation index is an important prerequisite for the correct assessment of examination findings. The normal values of corneal morphology vary among different populations, so we designed this multicenter study for Asians.

What was learned from the study?

While the anterior and posterior corneal curvatures (K1 and K2) increased with age, corneal astigmatism of the anterior and posterior surfaces (ΔK) and central, minimum, and overall corneal thicknesses decreased with age. Age-related decrease of the overall corneal thickness was more obvious toward the periphery. The anterior and posterior corneal surface heights exhibited a decrease and an increase, respectively. Both index of height asymmetry (IHA) and index of vertical asymmetry (IVA) exhibited an increase with age.

The cornea exhibits overall thinning with age and gradually changes from a flat ellipse to an elongated ellipse in Asian individuals with healthy eyes. However, the anterior and posterior surfaces become smoother with age. Therefore, with the increase in age, normal corneal morphology shows a gradual pseudo-protuberance state.