A model that closely resembles human excessive myopia can be prepared by mounting a minus lens (2) and a protector (4) to a juvenile mouse, the minus lens having an angle and a width adjustable in response to growth of the mouse. Further, this model analysis shows that myopia induction causes endoplasmic reticulum stress in a sclera and the endoplasmic reticulum stress induces myopia. Furthermore, it is revealed that an endoplasmic reticulum stress suppressant, particularly, phenylbutyrate and tauroursodeoxycholic acid act as a myopia prevention/suppression agent.
