I got reasonably good surfaces without filtering:
In addition to median and anisotropic noise filtering, you may also try unsharp masking (that has been reported to help with segmentation of thin structures, such as orbital bone), but with a few quick tests, I did not get significant improvements.
If you need to have continuous surfaces then you can try Wrap Solidify effect in Segment Editor (provided by SurfaceWrapSolidify extension).