It looks like your Plane is at the center of the Spheres, so everything under the plane is in shadow…It is hidden from view but will still cast a shadow.
the plane is far below the spheres and the direction of light is honest to where the shadow is being casted so i dont think there are any objects obstructing the spheres. i only added the two spheres beside the eye to determine if the lighting would behave on the same way. Its also a hassle since the socket doesnt seem to cast a shadow on the eye balls, it just remains half shaded
Does that mean they are straight above the Eye in your scene?
Is the eye made so there is an outer layer you want to cast shadow?
Gonna need more information and a better view of what you are doing.
Where are the Lights? What kind of lights? What are you trying to do, your end goal?
Show us a view of your scene ( hide the two spheres and any lights you added for testing) and show us the light settings.