White Pupillary Reflex in Photos

Question
Dear Becky,

We have a 5 yr. old dog named Mickey who we rescued from the Humane Society when he was about 4 mos. of age.  He's a handsome mix, although we're not sure of what!  ;)  He resembles Disney's "Tramp" (is about 50 lbs., and at a healthy weight), but is black w/ a white chest & forepaws, and has two differently colored eyes (brown left eye, blue right eye).

The eyes are what I am writing to you about, because I'm concerned about the fact that we frequently get a pronounced, white pupillary reflex from his left/brown eye when taking photos.  I asked our vet about this, but he claimed there was just a "different color vitreous fluid" in that eye -- ??

I've read just enough on the internet (it's hard to find the info. I'm looking for) to become increasingly concerned.  He seems healthy otherwise, but I worry there could be a problem lurking below the surface that hasn't been identified.  Do you have any experience with, or knowledge about, this particular issue?

I found references to "white pupillary reflex" and "leukocoria", but there can be a variety of causes.  Basically, "something" is preventing the light from reaching all of the way back to his retina, which is what produces the *normal* red reflex in photos.  However, I don't know if it's a congenital cataract, PHPV (persistent hyperplasia of primary vitreous), a retinoblastoma/other intraocular tumor, a detached retina, Coat's disease (fluid under retina), uveitis, or a large retina coloboma!  (I have no idea what most of those things even are!)

Is this something that's so infrequently encountered by the average veterinarian that we need to look at visiting an out-of-state specialist?  Or, do you think if I took this list of possibilities to our current vet, he might be able/willing to look into it in some additional depth?  Since you've worked for several vets yourself, I thought you would be a great person to ask!

Please let me know if you have any helpful information, links, or suggestions for us.  We are really attached to this dog!

Thanks!
~~~ Sara

Answer
Hi Sara!

It sounds like you have a really nice dog.  I can tell you love him very much.  Honestly, I really cannot help you.  The only thing I ever encountered when working for the vets, were cataracts.  I don't ever remember it ever coming up regarding the white pupillary reflex from the flash of picures.  I would think you need to take him to a specialist if it really bothers you.  Do you have a veterinary college close by? That would be a good place to go as students could also learn about it.
I hope you get some answers, as I know I haven't been much help!

God Bless,
Becky