Lenane la refractive la lense, 1.49, 1.56, 1.60, 1.67, 1.71, 1.74 letšoao le ka holimo la lense le bolela index ea refractive ea lense. Bakeng sa likhalase tsa myopic, ho phahamisa index ea refractive ea lense, ho fokotsa moeli oa lense, ka lebaka la hore likarolo tse ling li tšoana.