Coloboma or Ocular Marek's? Does it really matter?

[BuddingGardener]

Hi everyone!

I have a young-ish buff orpington (Hatch date May 9, 2023; nearly 9 months old) and I have noticed for at least a month -- possibly longer -- that she has one eye with a minor irregularity. There's some graying, the pupil still responds to light but to a lesser extent than her 'normal' eye, the whole flock was vaccinated upon hatch, and no one else shows any sign of illness consistent with Marek's. I've also been monitoring for as long as I've started to notice it and haven't seen any noticeable change or progression in the eye.

I don't really think there's anything to be done either way, just wanted to field some opinions. Thanks!

This one is the normal eye:

These are the 'irregular' eye in shade and full light:

 

[Eggcessive]

I would be concerned about possible signs of ocular Mareks, by the irregular shaped pupils, and the iris color looks to be fading. Does she seem to see okay? Some people with Mareks in their flock may only see the ocular form, but other symptoms could occur. A coloboma usually looks like a keyhole pupil, but the pupil outline is usually sharp, and the iris does not turn gray. They are common eye defects in birds and even humans have them, including my grandson. Here are some pictures of coloboma in different birds:
http://www.onthewingphotography.com/wings/2012/02/27/birds-with-blown-eyes/

 

[BuddingGardener]

I would be concerned about possible signs of ocular Mareks, by the irregular shaped pupils, and the iris color looks to be fading. Does she seem to see okay? Some people with Mareks in their flock may only see the ocular form, but other symptoms could occur. A coloboma usually looks like a keyhole pupil, but the pupil outline is usually sharp, and the iris does not turn gray. They are common eye defects in birds and even humans have them, including my grandson. Here are some pictures of coloboma in different birds:
http://www.onthewingphotography.com/wings/2012/02/27/birds-with-blown-eyes/

She seems to see just fine. She's active and runs up to me. One of my friendliest birds.

She does have a little bit of graying of the iris for sure, I'm just not really certain if this is something that's likely to progress in a vaccinated flock, or if it's anything I should be very concerned about. The rest of the flock has 100% normal eyes on both sides; three of them are older hens and approaching 2 years old. I watch my flock pretty closely for health abnormalities and haven't seen her worsen yet, but I'm leaving in mind the possibility that she could go blind in that eye.

 

[Eggcessive]

I really hope that it is not ocular Mareks, but please let us know how she gets along. There is a do it yourself blood test for Mareks that RAL does if you order the tools to collect it and send it back in. Blood is collected from a closely trimmed toenail, or blood drawn by a vet. Here is a link if you wish to do that:
https://www.vetdna.com/application/forms/aviansubmittalform.pdf

 

[BuddingGardener]

I really hope that it is not ocular Mareks, but please let us know how she gets along. There is a do it yourself blood test for Mareks that RAL does if you order the tools to collect it and send it back in. Blood is collected from a closely trimmed toenail, or blood drawn by a vet. Here is a link if you wish to do that:
https://www.vetdna.com/application/forms/aviansubmittalform.pdf

Ok! I would like to know if, practically speaking, this is something I must worry about intensely. I’m going for a vet follow up for my prolapsed hen tomorrow (she is doing very well) and I can ask his advice then. We practice good biosecurity, always have separate shoes when going out back to see the chickens (and separate clothes for when I visit a farm market or my equestrian lessons), and get vaccinated chicks. Aside from watching her function, is there hope that she can still be happy hen for awhile, considering she has been like this for at least a couple of months if not longer?

 

[Eggcessive]

The vaccine does not prevent Mareks 100%. It can help to prevent the paralysis. There have been many BYC posts over the years about vaccinated chicks later being diagnosed with Mareks. But it might be worth getting the test, just to know. It says it costs $20, but I think there are addition fees for the materials and postage. There is nothing that cures Mareks.

 

[BuddingGardener]

The vaccine does not prevent Mareks 100%. It can help to prevent the paralysis. There have been many BYC posts over the years about vaccinated chicks later being diagnosed with Mareks. But it might be worth getting the test, just to know. It says it costs $20, but I think there are addition fees for the materials and postage. There is nothing that cures Mareks.

I’ll ask my vet about this tomorrow. Maybe they can advise on testing for my buff Orpington.

 

[BuddingGardener]

@Eggcessive these photos are from early December and this is about the same as her eyes look now.

Edit: To be clear, I'm absolutely hyperfixating and worried. I don't want to think she's suffering in silence! She seems otherwise to be fine, and I don't know if showing this means that she has a breakthrough severe case and she's doomed regardless of the vaccination status.

 

[Eggcessive]

Well, they looked the same back then don’t they? I really hope it is not Mareks. I am just a chicken owner like yourself, not an expert. Let us know if there are any changes.

 

[BuddingGardener]

Well, they looked the same back then don’t they? I really hope it is not Mareks. I am just a chicken owner like yourself, not an expert. Let us know if there are any changes.

So sorry for my panic last night; I do have a clinical anxiety disorder and sometimes it gets a little out of hand. I've learned my lesson to calm down and think before I run to the internet!

In any case, I went to the vet follow up today and shared pictures of my buff. He has no reason to suspect it's Marek's due to the measures we take at home and her overall healthy condition and behavior. I've also checked and double-checked her eye and the difference is, to be perfectly honest, very subtle. There IS a difference and a narrowing of the pupil to a teardrop shape in the sun, but the subtle washing out of color is uneven and very very small, not completely around the pupil. Working hypothesis between my husband and I is that if she wasn't born with it, it could have certainly been caused by a near-miss hawk attack awhile back. She didn't have any visible terrible injuries at the time, but her comb received a gash and she was thrown against the side of our screen porch -- the same side with the strange eye.

So we will keep an eye on her and make sure she doesn't worsen, but for now, no reason to worry. We have strict biosecurity measures and a closed flock, so we are doing all we can for our girls.