Though the dioptre is based on the SI - metric system it has not been included in the standard so that there is no international name or abbreviation for this unit of measurement -- within the international system of units, this unit for optical power would need to be specified explicitly as the inverse metre (m). However most languages have borrowed the original name and some national standardization bodies like DIN specify a unit name (dioptrie, dioptria, etc.) and derived unit symbol "dpt ''.
si unit of power of a lens is
dioptre