Myopia Induction Measurements

At the beginning (3-week-old) and the conclusion (6-week-old) stage of the myopia induction, refraction, axial length and choroidal thickness were measured using an infrared photorefractor (Steinbeis Transfer Center, Stuttgart, Baden-Württemberg, Germany) and an SD-OCT system (Envisu R4310, Leica, Microsystems, Wetzlar, Germany). All measurements were carried out with mydriasis eye drops containing 0.5% tropicamide and 0.5% phenylephrine (Santen Pharmaceutical Co., Ltd, Osaka, Japan) and all were performed under MMB general anesthesia. The refractive values were measured with a continuous data trail. Along with the corneal vertex reflection, the axial length was measured from the anterior corneal surface to the retinal pigment epithelium^{40 (link)}. The choroidal thickness was measured according to the previous report^{22 (link),69 (link)}. Briefly, the mean choroidal thickness was computed by the choroidal area distant from the disc, at the border of the retinal pigment epithelium and the posterior surface of the choroid, the radius at 0.5 mm from the ringed disc was obtained by ImageJ quantitative analysis (National Institutes of Health, Bethesda, Bethesda, Maryland, USA). The average choroid thickness was then determined by dividing the area by the circumference.