Thank you for the pics.
Only you can tell up close and in person, but to me, that picture looks suspicious.
I will link Marek's information below. Ocular Marek's often creates a grey iris. The normal color of chicken eyes are gold, brown, orange, dark brown, or if albino, pink. Blue is not a normal coloring. It typically represents disease (either cancer or Marek's).
Marek's typically hits around point of lay, but can hit at any time.
Vaccinated birds can still get the tumors as the vaccine does not prevent virus transmission. The vaccines only help keep the tumors in check for certain strains.
If a bird's immune system is challenged by stress (such as coming into lay or move), the tumors can begin to overwhelm the immune system.
Depending on the type of virus strain, and I think even the bird's own immune response, tumors can grow in vital organs (producing wasting), in the nerves (producing the classic limp and leg split), in feather follicle (producing skin tumors), or in the eyes (producing discoloration of eye, typically in the iris).
So blue-eyed, grey eyed, appearing birds are suspect for Marek's.
Sorry.
I'm not a vet, so I don't know of the other conditions which might create an off colored eye like this. Some injuries could produce blindness, but that would look differently.
I'll link some photos and info on Marek's to help you diagnose your bird.
LofMc
http://extension.umd.edu/sites/extension.umd.edu/files/_docs/programs/poultry/FS-1007 Recognizing and Preventing Mareks Disease in Small Flocks.pdf
https://www.backyardchickens.com/articles/the-great-big-giant-mareks-disease-faq.66077/
http://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1321&context=extension_curall
