Next, reverse all of the optical surfaces in the system. This is easily done using the Reverse Elements tool (menu option, “Tools > Miscellaneous > Reverse Elements). When specifying the range of surfaces to reverse, include all surfaces except the Object surface and Image surface:

What needs to be done in the next step depends upon the nature of the original system:

In this example, the original system was afocal in object space and focal in image space, so, copy the Thickness from the surface before the Image surface to the Object surface:

We now have:

Next, we may need to change the “Afocal Image Space” check box in the Aperture tab of the General dialog. If the original system was afocal in image space, you should uncheck this box. On the other hand, if the original system was focal in image space (as is the case in this example), you should check the “Afocal Image Space” check box.

Likewise, we may need to change the “Telecentric Object Space” check box in the Aperture tab of the General dialog. If the original system was telecentric in image space, you should check this box. On the other hand, if the original system was not telecentric in image space (as is the case in this example), you should make sure this box is unchecked:

Lastly, we will need to convert our field definition as mentioned earlier. Since our original system was afocal in object space and focal in image space, we will use the original chief ray image coordinates to set the field points in the reversed system as Object Height:

If you now open a new layout window, you can see that the optical system has been successfully reversed: