Refractive error is a main cause of visual impairment and blindness around the world. Active screening to identify children with uncorrected refractive error and treating them throught the provision of spectacles is recommend in many countries. However, it is not clear what the best screening stratergy is. Therefore, this study focus on development of system for screeening and correcting refractive errors in pre-school and school children in Thailand. It is expected that results from this study can be used to formulate policy recommendations for the Universal Health Coverage Scheme in Thailand.