More than 2.3 billion people in the world suffer from poor vision due to refractive errors (REs). Uncorrected REs are the largest cause of avoidable blindness in the developing world.

Visual impairment can have immediate and long-term consequences in children and adults, such as lost educational and employment opportunities, and impaired quality of life. REs can simply be diagnosed, measured, and corrected with the aid of optical corrective approaches and devices such as spectacles and contact lenses or by refractive surgical procedures. Current data suggests that more than 90% of people with uncorrected REs worldwide reside in rural and low-income countries.