Cylindrical powers are usually genetically determined, and are present from birth. They are generated due to the ‘shape’ of the cornea (it being more egg shaped vis a vis orange or spherical in shape).There may be some family member on either side of the family with cylindrical powers. It is this genetic tendency that has been expressed in the child as the cylindrical power. These powers are usually stable or constant. The child should use the glass regularly for better clarity of vision. These are no precipitating causes for the condition.