It’s blue

 

Potential blue glow
Blue glow of the eye

I added 2 blue LEDs through some current-limiting resistors. The result is actually quite bright. Trying to get all of this into the space was fairly difficult. The servo has to stick out far enough for the wire and the servo horn to move but in enough that it does not hit the curved wall.
I wanted to be able to remove the eye completely. Consequently I added a terminal block so I could unscrew the wires if needed.

DR SLR

Working on the eye stalk I found that making an iris that has a smooth action is hard to do. I actually made 3 designs, based on designs I found on the internet. In the end I chose to go the easy route.

Eye iris
Future iris for eye

I looked in second hand shops for an old 35mm SLR style camera but either could not find them or the ones I found were too pricey. I had an old Pratika MTL5 circa early 1980s which I chose to take apart. When all’s said and done the iris moved very smoothly.