White, glassy eye - cataract?

Question
Hello Dr. Krempels,
I have a 2 yr old neutered Rex rabbit who has had eye problems for about a year. He started to have a white little dot that grew into a white, hazy mark on his eye. I took him when I first noticed the white dot to Univ. of Penn's vet hospital where the eye speciaists ran tests. They weren't sure if it was a sort of bug he has had since birth or cataracts or glaucoma, but they predicted that short of surgery, there was nothing I could really do. They thought it was a type of virus that will be with him for his life.

They gave me drops for him, but that did not stop the white mark from taking over his whole eye. It now looks like a marble. He doesn't seem to be in pain, but I'm wondering if you know if this sounds like anything you've seen, and if rabbits are in pain?
I love him so much, but I'm a grad student and can barely afford the $350 of tests it cost, let alone the $5,000 surgery. I do want to be sure that he is not in pain though.

Thanks for any input!

Answer
Dear Marissa,

If the veterinary ophthalmologists suspected that your bunny's eye lesion is due to a parasite (Encephalitozoon cuniculi), then the only treatments would be Panacur (fenbendazole), and/or ponazuril (toltrazuril sulfate).  Neither of these would be likely to cure the eye problem, but they might have arrested the progression of the problem--or not.  Very difficult to say, as these drugs work well sometimes, and sometimes not.  

The odd thing is that this is unilateral.  E. cuniculi cataracts are often bilateral.  And if there is truly a suspicion that the cataracts are due to E. cuniculi, then I would ask your vet about putting the bunny on Panacur and/or ponazuril, to prevent further degeneration, if possible.

If the problem is due to glaucoma, then the vets should have been able to detect this by checking the intraocular pressure.  There are medications that can control this problem.  And this is actually more likely to occur unilaterally, though rabbits predisposed to glaucoma often develop it in the second eye later.  So it would be wise to monitor the situation, have the IOP checked in both eyes, and ask for appropriate treatment, accordingly.

A bunny can be fine with only one eye, and I even know of very happy blind rabbits.  But it's better to have sight, of course!  

If possible, try to get a boarded veterinary ophthalmologist to look at the bunny's eyes--and not vet students.  A veterinary ophthalmologist will really be the one to know what tests to run for glaucoma, and hopefully know what the characteristic cataracts caused by E. cuniculi look like so this can be treated, if that's what the problem is.

I hope this helps.

Dana