There is no part in the originals files to fix the eyes in the dragon's head. I designed a clip to solve the problem.
-You need to put one eye in the head, then put the other with the clip attached.
-With a tool (plier, tweezer) insert the free side of the clip in the second eye. This is the hard part. You need to roll the eye (the one without clip) and slowly push the clip in it.
-The clip must be in the right position otherwise the dragon will squint (see the first picture).