The present invention provides a screening method for searching a component inhibiting the PERK pathway and/or the ATF6 pathway, and by obtaining, by the screening method, an active ingredient inhibiting myopia progression without impairing normal growth of the eyeballs (emmetropization) in children, provides eyedrops and a composition containing the active ingredient. The problems are solved by eyedrops for inhibiting myopia progression in children containing, as an active ingredient, an inhibitor of the PERK (PKR-like endoplasmic reticulum kinase) pathway and/or the ATF6 (activating transcription factor 6) pathway. The problems are solved by a screening method for an inhibitor of myopia progression in children, including a step of contacting a candidate substance with an eye-derived cell, and a step of selecting the candidate substance using, as an index, change in a protein and/or a gene of the signal transduction system of PERK and/or ATF6.