Is her eye color gray like the one below, or is it cloudy? Mareks still could be a possible problem because of the lameness, wasting, and if the eye is changing in color. If you feel like she is suffering, you may want to put her down, or get her euthanized. The state vet or poultry lab can perform a necropsy to look for what is wrong with her, and they can also euthanize. Here is some info about necropsy and state vets:
http://www.metzerfarms.com/PoultryLabs.cfm
http://www.usaha.org/Portals/6/StateAnimalHealthOfficials.pdf
http://www.metzerfarms.com/PoultryLabs.cfm
http://www.usaha.org/Portals/6/StateAnimalHealthOfficials.pdf