A lot of research has been done to find an answer to this question.This actually has a strong genetic component although there may be exceptions to the rule. Usually if one parent is near sighted (Myopia) or far sighted (Hypermetropia) the chances of child having the refractive error is about to 25-30%.

If both the parents are wearing glasses, then the risk ratio of child inheriting it goes up to 60%.There are no benchmark figures as this can be affected by the severity of refractive error which means, if both the parents have high myopic of e.g.: -10.00D, they are more likely to pass it to the children than both parents who have about -1.50 D refractive errors.Similar results have been seen for ‘+’ no’s (hypermetropia) & astigmatism (cylindrical number).

But we have to remember Environmental & nutritional factors also contribute to development of myopia.Children spending too much time indoor & focusing on near objects such as reading & excessive gadget use have increased risk of developing myopia.