Bulb detail...

This lamp assembly is made from various bits of plastic with the bulbholder glued to the end.
A brass retaining nut has been glued into a hole in the underside of the assembly.

The whole assembly can be unscrewed and then replaced, once the eyeball has been added.
The wire is channelled up the central threaded tube and then through the brass nut.

A small notch has been cut in the bulbholder to allow the wires to connect to the terminals.