Marco 3D wave confirming the proper placement of a toric intraocular lens (IOL). The top left image is of the axial or anterior corneal astigmatism and measures dK of −1.94 D of astigmatism. The bottom left is the internal optical path difference (OPD), which includes anything posterior to the IOL. The measurement of cylinder is +1.74, leaving a residual of 0.20D of astigmatism. An internal OPD of 90 degrees from the axial topography confirms the proper placement of a toric IOL.