More than one in three children and teenagers already suffer from myopia, or shortsightedness, but experts say this number will rise sharply over the next few decades

More than one in three children and teenagers worldwide are shortsighted, according to the largest study of its kind, prompting calls to discourage screen time and increase physical activity.

Shortsightedness, or myopia, is an eye condition where someone cannot see objects far away clearly. It is usually corrected with glasses or contact lenses.