Popular request these days lol ...
Here’s are a couple of models already made. Have no idea how they might work but for the price hopefully there’s support if needed.
http://www.turbosquid.com/3d-models/surgical-microscope-carl-zeiss-3d-model/642127
http://www.turbosquid.com/3d-models/phoropter-3d-model/698837


