Please tell me this is cataracts

[Cellomama2]

I have a bantam speckled Sussex that is 3.5 years old that I have been watching the last few weeks loose more and more of her ability to see. I was assuming that since I got her from a backyard breeder it was possibly some sort of genetics/cataracts starting but looking online is freaking be out thinking possible Mereks because in this picture I took tonight her pupal doesn't look completely round. Her pupal does still react to light but when she walks she seems lost. I'm hoping that I'm over reacting as she's just getting old but I'm not sure what to do at the moment. I will take any better pictures you need just tell me what angle you need them at.

 

[Wyorp Rock]

@Eggcessive what do you think?

 

[Kiki]

How long have you had her?

When was the most recent time you added anyone new to your flock....how long ago?

 

[Eggcessive]

I am not an expert on Mareks disease, but I think there is a possibility that she could have the ocular form of Mareks disease. It can gradually cause the eyes to grey in color, and the iris can change shape to make the pupil look less sharp. But I have also read where avian encephalomyelitis (also called epidemic tremors) virus can also cause cataracts and grey eye. It usually affects young chicks in their first month, and cataracts can result in a few survivors. Here is a picture of ocular mareks, and below is a video that has a picture of AE cataract:
https://upload.wikimedia.org/wikipe..._disease.jpg/220px-Ocular_Marek's_disease.jpg

 

[Cellomama2]

Eggcessive
Thank you, I'll look into this more closely.

 

[Cellomama2]

Kiki
I got new ones about 3 months ago now but they aren't together and I practice pretty good bio security with new birds. The last ones were added last August but no one has shown anything like this except her and we've had her for about 2.5 years.

 

[Eggcessive]

Mareks disease usually affects young chickens, but older chickens can still be affected if a carrier is brought into the flock. It takes at least 3 weeks after exposure for a chicken to have symptoms. Mareks is spread through feather dander, so it would be hard to prevent it from spreading in the environment. Blood serum can be tested for $20 at a Texas lab Vetdna.com on live chickens. Here is some reading about Mareks:
https://www.backyardchickens.com/articles/the-great-big-giant-mareks-disease-faq.66077/

 

[Cellomama2]

I thought it said that the testing isn't 100% accurate though.