My rabbit is blind, what tests can be done?(& Life span qs.)

Question
Thank you for the info, my bunny's behavior seems normal & he has always had a good appetite. My bunny's eyes & pupils are not white. Does this definitely rule out cataracts? Does it rule out all kinds of parasites & infestations of any kind that may have caused the blindness? Does it rule out any other condition? Also, are there rabbit opthamologists at the U of Penn or anywhere else in south eastern PA? We just saw a new exotic animal specialist vet that's been seeing bunnies for about 18 years. She seems much more thorough & knowledgeable then the two other exotic animal specialists that have previously examined our bunny. However, She did not mention removing the eye lenses. I will speak to her about this & I'll find a bunny opthamologist. As for light sensitivity, I know my bunny sometimes squints at bright sunlight, but I'm not definitely sure he squints at lamps, he still usually sleeps w/ his eyes closed & seems to 'squint' when waking from sleep, when stretching, etc. Is the lens removal procedure complicated, i.e. will my bunny need general anesthesia, pain medication afterwards, & are there any risks of injury during surgery? How long is the recovery time & what does it involve? Any more info you can give about this procedure would be very helpful.
I also have another question. As I mentioned, our Rex rabbit (our only rabbit) is 4 years old. He is 5.8 pounds & I'm surprised he's not bigger at his age. I'm wondering if he might be a Mini Rex, instead of a regular Rex, although none of the vets have mentioned this possibility. Do you know how to tell the difference between the two kinds of Rex rabbits? And at what age do rabbits 'stop growing' & reach their full adult size? My bunny has large, fully developed (adult sized) hind legs & feet & he's always had very large ears, even as a baby, so we know he's not a dwarf. Do Mini Rexes normally have a shorter life span than regular Rexes? And how accurate are those 'life span estimates' given to different breeds of rabbits, anyway? Thank you again, all info on these two topics will be very helpful. Janene
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Followup To

Question -
Hello, My boyfriend & I are parents to a male, un-neutered Rex rabbit. He is 4 years old, VERY smart & communicative & blind in both eyes. He was blind when we adopted him from a local animal fair, when he was about 8 to 10 months old. We just learned of a glacoma test from our new vet & tested him right away & were happy to learn that he doesn't have glacoma. :) He does not seem to be in any pain, he is VERY affectionate, very playful & LOVES to snuggle! He's had minimal reaction to a close-up beam of light when he's been examined by different exotic animal specialist vets. He does squint at some light from close lamps(it seems) & definitely from sunlight, so we think he can see some shapes & light. Is there any other tests we can do to determine the cause of his blindness & to make sure he is not in any pain? (And how common is blindness in rabbits? Are blind rabbits usually blind from birth?) Thank you for your advice, it is very much appreciated. :) Janene

Answer -
Dear Janene,

If your bunny is sensitive to light, then his retina is apparently working to some degree, at least.  If his pupils are white, then it's possible that his blindness is due to cataracts (which can be caused by things other than glaucoma, including a parasite known as Encephalitozoon cuniculi; if this is the case, then he should probably also be treated fo r 28 days with Panacur (fenbendazole) or oxibendazole to prevent other problems related to E. cuniculi).

I would get him to a good veterinary ophthalmologist for evaluation of his visual capacity.  If you're willing to spend big bucks, and if the vet thinks it would be worthwhile, you could consider having his lenses removed (though I would NOT bother with the expense of lens replacement, as rabbits don't have good close vision, anyway).  This would allow him to see (not too focused) shapes and movements.

Blind rabbits are not always blind from birth.  Since you got him that way, there's no way to know when he became blind, but if his retinas are functional I would guess that he is not congenitally blind.  A veterinary ophthalmologist can tell you more.

Unless he has uveitis or glaucoma, it's not likely that he's in pain--especially if his behavior is normal and his appetite good.

I hope this helps.

Dana

Answer
Dear Janene,

I'll try to take your questions one at a time:

1.  If the pupils are not white or cloudy, then the bunny probably does not have cataracts. This would make lens removal surgery pointless.  The surgery is complex and painful, and it does require general anesthesia.  But if sight can be restored, it is worth considering.  I fear in your bunny's case it may not be.

2.  I cannot begin to guess the cause of his blindness without more information about his history (which is probably not available).  But a good veterinary ophthalmologist probably could give you some ideas.

3.  I don't know the vets in your area, but your exotics vet should be able to give you a referral, if you ask.

4. Your rabbit is fully grown at his age.  Growth usually stops by the age of one year.  Your bunny could be a mini-lop or a dwarf bunny with Rex fur at that small size, but also might not be purepred, so hard to say about the breed.

5.  In my experience, Rex rabbits, and particularly mini-Rex/dwarf Rex rabbits live a *very* long time, all other things being good.   Our Fala was at least 13 when she finally left us, due to complications from a thymoma.

Hope this helps.

Dana