I have very often problems with rigid body objects. Almost every time objects have to be huge that they works. This eye; I make it about 100x bigger and then it works good, but not in fast moves like in video. Changed also “eye frames” from Convex Hull to Mesh and made Margin to 0.0001m, but still it fly away.
.blend-file: https://filebin.net/ays6bo10pvibkx68
Important for rigid body simulation is: You have to keep an eye to the normals in the right direction.
Your eye has wrong normals. → select → edit mode → shift-n
Then in rigid body settings: delete bake and set substeps and solver to 100 (that is needed for fast movements so that Blender can calculate correctly)
result:
Hi, as for your last question about the eyes look at this file i have deleted all object except the eyes for uploading:
Lumiukko_kouluprojekti_4_3.blend (2.2 MB)
Oh thank You, this substeps is totally new for me!
And this, You fixed it in project different way!
It’s so amazing that I got two different solutions so quickly. And sorry digitvisions, I can only choose one solution (whichever came first).
God blessings kind Blender-friends 
