Methods
Axis
IOL, ACD, LENS, REFRACTIVE ERROR, CYCLOPLEGIA
After systematic ocular examinations, the corneal curvature, the corneal and pupil diameters were measured by the corneal topography (Medmont E300, Australia). The axial length (AL), the central corneal thickness (CCT), the anterior chamber depth (ACD) and the central lens thickness (CLT) were examined using IOL Master 700 (Carl Zeiss 700, Germany). The refractive error in each eyeball was subsequently measured by the autorefractor (KR-8800, Topcon, Tokyo, Japan) after sufficient cycloplegia cyclopentanone eye drops (1%), and three designed measurements were averaged. The refractive error was recorded as Sphere (S), Cylinder (C) and Axis (A), and then the spherical equivalent refraction (SER) was calculated using the sum of the spherical power and half of the cylindrical power (SER=S+C/2). The slit lamp (SL-D8Z, Topcon Optical, Tokyo, Japan) was used to check the anterior segment of the eye before and after wearing the orthokeratology lens and to evaluate the suitability of the lens. The participators in SVS group were given SVS for wearing, while the children in Orth-K group were given Orth-K for wearing. The keratoplasty parameters included: lens material, Boston XO; lens diameter, 9.80 - 11.60 mm; optical diameter, 5.50 - 6.00 mm; oxygen permeability coefficient, 100 × 10 