Poor Pupillary Light Responses

[19mac]

Hi all

I'm wondering if anyone has had experience with a dog with mature cataracts and a slow pupillary light response but successful cataract surgery?

I've read everything written about cataracts experiences so far in this forum but I haven't found anyone in the same situation as my dog. He's a 12 year old maltese X shih tzu with mature cataracts and we had our first consultation at the ophthalmologist today. They found he had limited pupillary light response but we were told that there can be various reasons for this - so an Electroretinogram (ERG) and an ultrasound were suggested. We've been told that my dog has a 50/50 chance that his retinas are healthy (which we'll find out after the ERG and ultrasound) to determine if he is an eligible candidate for surgery.

I would love to hear everyone else's experiences, with the ERG and ultrasound - particularly if they have an older dog with cataracts?

Thanks

Edited June 13, 2014 by 19mac

[Pretty Miss Emma]

You no doubt then will have read about my experiences in dealing with cataract surgery with my old girl, so I won't rehash that. I would suggest send Kirty a PM, or no doubt she will see this at some point, as she might be able to give you some insight on this.

I don't regret doing the surgery for my dog, but I would think twice about it if I had to do it again - mainly because dogs adapt really well, and I think I did the surgery as much because I wasn't coping with her going blind more than her not coping. And don't forget, any surgery in an older dog carries a much greater amount of risk than in a younger dog. Just something to think about.

[*kirty*]

Hi, I work at an eye specialist so hopefully I can help.

The PLR tells us that the eye is responding to light. It is not necessarily indicative of vision. There can be lots of reasons that a dog has a slow or poor PLR.

Sometimes the muscles in the iris (the coloured part of the eye) can become atrophied due to age, so we get a poor PLR. In this case, the retina (nerve tissue at the back of the eye) may be perfect so cataract surgery is still an option.

However sometimes if the cataracts have been present for a long time, they start to leak inside the eye. This is not something you can see, its happening on a microscopic level. This leaking causes inflamation inside the eye, and this inflamation can cause damage to the retina and will also cause a poor PLR. It can also cause the retina to detach and that will also cause a poor PLR.

The only way to know if the retina is healthy and your dog is a good candidate for surgery is to do the ERG. When the dog is under anaesthetic, probes are attached to the face and eye. A bright light flashes into the eye and a computer measures the response. This tells us instantly if the retina is working properly. The ultrasound shows us if the back of the eye is normal - we can check that the vitreous (jelly at the back of the eye) is healthy, that the retina has not detached, and that the back of the lens has not ruptured.

If all of these tests are good, we can go ahead with surgery. Unfortunately no surgery is guaranteed. Mature cataracts always have lower success rates due to the inflamation they have caused inside the eye. But there is still a good chance that your dog will get useful vision back. We could give someone a 90% success rate and their dog could be in that unlucky 10% that has complications.

As Pretty Miss Emma said, blind dogs cope very well. There is no right or wrong answer here. It's entirely up to you. Personally I would get the ERG done so you at least know where you stand and what your options are. :)

[Her Majesty Dogmad]

A dear friend just had surgery done on her cocker spaniel (rescued), who's only 6 yrs old.

Sadly it didn't work. Dogs are amazing at adapting, just made sure you don't move furniture around or leave obstacles in the way and cut back all bushes in the garden (or avoid them) so there are no pokes in the eye.

[*kirty*]

Was that in NSW Jane? I believe they don't do ERGs in NSW and with a 6yo Cocker I would be very suspicious of PRA.

[Pretty Miss Emma]

We could give someone a 90% success rate and their dog could be in that unlucky 10% that has complications.

As we know!!!

[*kirty*]

Yep, poor little Emma was very unlucky.

[19mac]

Hi, I work at an eye specialist so hopefully I can help.

The PLR tells us that the eye is responding to light. It is not necessarily indicative of vision. There can be lots of reasons that a dog has a slow or poor PLR.

Sometimes the muscles in the iris (the coloured part of the eye) can become atrophied due to age, so we get a poor PLR. In this case, the retina (nerve tissue at the back of the eye) may be perfect so cataract surgery is still an option.

However sometimes if the cataracts have been present for a long time, they start to leak inside the eye. This is not something you can see, its happening on a microscopic level. This leaking causes inflamation inside the eye, and this inflamation can cause damage to the retina and will also cause a poor PLR. It can also cause the retina to detach and that will also cause a poor PLR.

The only way to know if the retina is healthy and your dog is a good candidate for surgery is to do the ERG. When the dog is under anaesthetic, probes are attached to the face and eye. A bright light flashes into the eye and a computer measures the response. This tells us instantly if the retina is working properly. The ultrasound shows us if the back of the eye is normal - we can check that the vitreous (jelly at the back of the eye) is healthy, that the retina has not detached, and that the back of the lens has not ruptured.

If all of these tests are good, we can go ahead with surgery. Unfortunately no surgery is guaranteed. Mature cataracts always have lower success rates due to the inflamation they have caused inside the eye. But there is still a good chance that your dog will get useful vision back. We could give someone a 90% success rate and their dog could be in that unlucky 10% that has complications.

As Pretty Miss Emma said, blind dogs cope very well. There is no right or wrong answer here. It's entirely up to you. Personally I would get the ERG done so you at least know where you stand and what your options are. :)

Hi Kirty -

Thanks so much for this info - while the opth said there may be a variety of reasons for poor PLR, they didn't give any details so this really helps us have a little hope. Best case scenario would be my dog Alex wouldn't have any problems navigating around the house & yard, but he's been getting 'stuck' in various places around the house he's been for years - ie. he'll stand facing a wall wanting to go out thinking it's the door, and combined with the fact that I'll be moving him interstate with me (regardless of how his eyes are), I'm really worried that he'll struggle to settle in.

The opth did note that he had minor inflammation, and we've been prescribed some anti inflammatory eye drops for a week before the ERG, and we were given a rough ballpark of 70-75% success (this is a general estimation and it's a much lower rate than normal due to potential post-op complications due to his age and maturity of cataracts).

With that said, he's in excellent health otherwise (still bouncy and energetic to the extent no-one knows how old he is unless they see his eyes, and he's always up for a walk/play and loves his food) and the general vets found nothing wrong with him prior to the opth consult, so hopefully that works in his favour.

I was always going to to go ahead with the ERG & Ultra - I figure I have to explore all the options at least, and at least I know I did everything I can for him, but I don't want to be set up for false hope if there isn't much chance we'll get a positive reading with the ERG.

Regardless, if it turns out there isn't anything that can be done for his eyes, I'll have to make some adjustments and look into resources that make it easier for Alex to get accustomed to a new home and find his way around the new house.

Thanks again!

Edited June 15, 2014 by 19mac

[19mac]

A dear friend just had surgery done on her cocker spaniel (rescued), who's only 6 yrs old.

Sadly it didn't work. Dogs are amazing at adapting, just made sure you don't move furniture around or leave obstacles in the way and cut back all bushes in the garden (or avoid them) so there are no pokes in the eye.

Unfortunately, we haven't been moving anything around but Alex seems to be getting a little confused around the house + moving interstate to a new environment makes it a bit more complicated.

We're just taking it one step at a time right now, and if the ERG & Ultra come back negative next week, then we'll have to go down a different route to settle him into his new place.

[19mac]

You no doubt then will have read about my experiences in dealing with cataract surgery with my old girl, so I won't rehash that. I would suggest send Kirty a PM, or no doubt she will see this at some point, as she might be able to give you some insight on this.

I don't regret doing the surgery for my dog, but I would think twice about it if I had to do it again - mainly because dogs adapt really well, and I think I did the surgery as much because I wasn't coping with her going blind more than her not coping. And don't forget, any surgery in an older dog carries a much greater amount of risk than in a younger dog. Just something to think about.

It's definitely something we're keeping at the back of our minds through this whole process - thanks for the advice :)