Summary

Sony PS3 Eye USB Cameras can be modified to take other CCD lenses with M12 mounts. For some lenses this can throw out the focus range.

These are some very simple 3d printed shims that sandwich between the sensor assembly and the lens to correct the focus range.

Instructions

For actually dismantling the PS3 Move Camera and separating the lens from the mount, I recommend this page at Instructables:
http://www.instructables.com/id/The-EyeWriter/step6/Hack-the-PS3-Eye/

The shim fits between the black plastic lens mount and the sensor PCB. The shim will prevent you from using the locator pins on the lens mount to position it on the PCB before screwing it in, so you'll have to be careful to put it on straight and not accidentally touch the sensor. There's actually a lot of room so it's not as precarious as it sounds.

The attached .scad file and .STL both print 3 shims - 1.0mm, 1.5mm & 2mm. I recommend trying 1.0mm first and only fitting a larger shim if you can't get a full focus range. After you mount the lens with the shim, you will need to screw the lens in and out until you find a position that allows a full range of focus.

The 2mm shim may mean you need to use a longer mounting screws, the 1.0 & 1.5mm seem to work OK with the existing screws.

I recommend using a dab of hot glue (or similar) to hold the shim in place on the lens mount, as shown in the photo, before you try to locate it on the sensor PCB.

PS3 Eye Camera Lens Shim