I went searching for that post. I think the problem is just that the model is wearing coloured lenses (possibly not even for eyesight reasons).
AFAIK /all/ normal contacts are single colour, so any modification would be across the whole of the iris and pupil, and thus quite discreet.
I think that you can get some coloured dioptric lenses, but generally not very strong I think unless you pay hundreds (well it was the last time I checked my prescription).
Also, if they are lenses for eyesight reasons, then I think the model might need to go and have a checkup. Recently I was told that mine were not sitting right (too low), and thus a slightly different curvature was required. Possible the same applies to this model