There is some evidence that atropine eyedrops retard myopia progression in three randomized clinical trials. It is believed that atropine act on muscarinic receptor located in the sclera and through some unknown mechanism retard the elongation rate of axial length. However, the possible long-term side effects such as cataract formation and retinal toxicity, are largely unknown. Photophobia in daily life, accommodation difficulty both decrease the acceptance of atropine usage and compliance.