Pet owner gets help with their cat’s eye problems

Hi XXXXXXX,

I am glad to have been of help. If I didn’t know as much about his medical history as I do now, I would be more suspicious of high BP being involved in his blindness than I am now. It certainly is something that we see much more frequently than taurine retinopathy or PRA, and I believe in always ruling out the obvious causes before chasing after rare ones.

I can’t logically come up with a connection between the fever and the stenosis. Widespread blood infection could cause vegetative endocarditis, but the cardiologist wouldn’t have confused that with the stenosis. I did a search in a vet database for connections with blindness and his heart conditions and the only think I pulled up was blindness can be a rare complication after anesthesia but it was only seen (and again, this is very rare) in cats with hypertrophic cardiomyopathy. An obvious connection doesn’t seem to be out there that we know of.

I am not concerned about the herpes–I always have at least one cat with herpes in my house at any given time. It’s not a big deal usually. You can add lysine to his food if you don’t already to help prevent flare ups. My cats won’t accept the powder on their food so I get the lysine cat treats–he loves them. I buy them on amazon.

Excess taurine is just excreted in the urine, so you won’t be putting him at any risk by starting immediately.

He is a handsome little man for certain. I am sorry he seems to have some huge obstacles to overcome.

Check out our community and please share updates and photos on our facebook page–I usually do the posts on there. I’d love to learn what the experts say and I hope good luck finally finds it’s way to Conrad!

response by XXXXXXXXXXXX on 2011-10-19 17:37:20

Hi Dr. Laci,

WOW. This is an amazing amount of information… We are so very appreciative. Yes, his eyes glow like the cat in the photo you attached, though they are much more dull. I was finally able to attach a photo; it was taken in bright light, and as you can see (if you can get past how unbelievably cute he is), his eyes are almost all pupil.

I just called his vet and a kitty cardiologist he once saw; no one ever took his BP. I set up an appointment for that. Could his BP be affecting his vision? Also, he actually has pulmonic and aortic (not mitral and tricuspid) stenosis. He had a high (almost fatal) fever when he was about four months old, so perhaps that’s what caused his heart condition?

Yes, his vet checked him for FIV and FIP. I also forgot to mention that he has feline herpes. His eyes get a little red and crusty during his flare-ups, but it mostly seems to affect his nose, which is relentlessly dry and crusty (sometimes to the point where it starts to split down the middle and we have to treat the boo-boo with Vaseline!).

We will also take him to an opthalmologist, but in the meantime we will start him on twice daily taurine supplements.

Let me know if you have anything to add based on this new info. And again, thank you so, so much for your unbelievably detailed and helpful reply.

~Julia

response by Dr. Laci Schaible on 2011-10-19 16:56:23

Oh, I forgot to answer your question about pulmonary hypertension–yes, it can cause the retinas to detach. It is usually acute, but if the pressure if brought under control, the animal can regain vision. I don’t think it sounds like what Conrad has, but it would be just awful to miss it. Most vets can recognize it on visual exam if they have some basic equipment, so I am not sure if your vet was concerned about this/ruled it out.

response by Dr. Laci Schaible on 2011-10-19 16:53:41

Thanks for your answers. I believe your idea about taurine is an excellent one, and I want to talk about that one first. Taurine retinopathy, also called feline central retinal degeneration, is deterioration and death of the retina that is caused by a deficiency of taurine in the diet of cats. Taurine is an essential amino acid (a building block of proteins) that must be supplied in their diet because cats cannot manufacture it themselves.

Within just 10 weeks of eating a diet low in taurine, the cone photoreceptors of the retina begin to deteriorate. The cones are responsible for bright-light and color vision. Within 20 weeks, many of the cones are dead. If taurine remains deficient, eventually the rod photoreceptors (responsible for dim light vision) are also affected. Taurine affects both eyes in a symmetrical fashion, and the end result is complete blindness.

Taurine deficiency also causes dilated cardiomyopathy in cats, a disease of heart muscle. The two conditions can occur alone or together in any individual cat.

It’s only been since 1987 we’ve learned this and commercial cat foods have been manufactured with a higher content of taurine. For the past 2 decades, the incidence of taurine r

etinopathy has steadily declined. Cats that consistently eat a well-balanced commercial food rarely develop the disease, and it is not understood why. Taurine retinopathy may occur in cats that eat predominantly dog food, because taurine is not supplemented in canine diets. Dogs can make taurine themselves from other dietary components.

Taurine retinopathy is also sometimes found in cats that have been strays and in those exposed to poor-quality food. Rarely, the retinopathy occurs in cats that are fed good-quality commercial foods containing adequate taurine levels (500-750 parts per million), for reasons unknown. I am not familiar with Best Feline Friend but they do have taurine listed in their ingredients. If he comes up taurine deficient, I would certainly place a call (or have your vet) to find out what level taurine is in the food.

Initially, vision is not substantially altered, and affected cats have no clinical signs. As the disease progresses, the cat may bump into objects, stop playing with toys or chasing objects, be reluctant to go outside, or act lost and confused. Owners may notice a change in temperament as you did. Eventually, the pupils become dilated, and the eye shine (tapetal reflex) from the back of the eye may become more visible (sounds like what you describe).

How to find out if Conrad is taurine deficient–

Taurine retinopathy can technically be diagnosed from an eye examination, because certain changes characteristic of taurine deficiency can be seen in the retina, but as the deficiency is no longer that common in cats that go to the vet, it’s something most general vets aren’t used to seeing. As the disease worsens and creates widespread changes in the retina, the condition becomes similar in appearance to inherited progressive retinal atrophy (another slowly developing retinal degeneration of cats—more on this later). If the diagnosis is uncertain, your cat may be referred to a veterinary ophthalmologist for evaluation of the retinas.

If taurine retinopathy is discovered or suspected, a blood taurine test is frequently recommended. If the blood taurine level is low, the diagnosis of taurine retinopathy is confirmed, and further evaluation of the heart is indicated.

If the cat is on a poor or unbalanced diet, then a good-quality commercial cat food is provided. Treatment also involves supplementing the cat with extra taurine, usually once

or twice daily in pill or powder form. Supplementation is often continued indefinitely. Additional treatments are needed if dilated cardiomyopathy is present.

Taurine retinopathy can be stopped but not reversed. The areas in the retina that have degenerated by the time of diagnosis will never function again. With adequate taurine supplementation, the remaining healthy part of the retina is protected and the disease does not progress (worsen). If the cat is already blind, the blindness is irreversible. Even in blind cats, however, taurine supplementation is worthwhile, because it will prevent dilated cardiomyopathy.

Now there are other causes of retinal degeneration—largely referred to as progressive retinal atropy. I am suspicious that the retina may be degerating because of how you describe his eyes as looking like they are burning embers. That to me sounds like they are shiny or metallic looking. Cats have something called a tapetum lucidum—a layer of tissue in the eye that reflects visible light back through the retina, increasing the light available to the photoreceptors. This improves vision in low-light conditions. As the retina degenerates, the tapeum is more and more visible. I’ve never heard it described before as burning embers, but it kind of does. I’ve attached a picture of “regular-eyed” cat whose tapetum is visible.

Back to Progressive retinal atrophy…this is a group of inherited diseases of the retina that lead to blindness. Two forms of PRA exist. In the early form, the cells in the retina that detect light (photoreceptors) do not develop normally. In the late form, the photoreceptors develop properly, work well for several years, and then degenerate. PRA is usually found in pure-breed cats but can effect mixed-breeds as well.

Most forms of PRA are inherited as an autosomal recessive trait, which means that the affected cat has inherited one abnormal gene from each parent.

PRA affects both eyes. Because rods are involved initially in most cases, nighttime vision is lost first. Eventually, cones are affected and the animal goes completely blind. The age at onset and rate of progression depend on the type of PRA present. Most early-onset forms begin when the animal is several weeks old; signs are noticeable by 4-6 months of age, and the animal is often blind by 6-12 months of age. With late-onset forms, the disease begins at 2-6 years of age in some breeds and is delayed until 8-10 years in others. So our range is wide here.

Signs that may initially be noticed at home include reluctance to go down stairs in dim light, into darkened rooms, or outside at night. At the disease progresses, the animal may bump into objects in dim light, may not be able to catch tossed objects, or may act lost or confused. Eventually, the animal bumps into objects in bright light, the pupils become dilated, and the tapetal reflex from the back of the eye may becomes more and more visible.

Because vision is not the most important sense for dogs and cats, and their senses of smell and hearing are much better than ours, many affected animals behave normally early in the disease. The disease can be quite advanced before any symptoms are detected, and the actual onset of complete blindness can be hard to determine.

Early in the course of the disease, few changes may be detected in the eye examination of affected animals. If PRA is suspected, an electroretinogram (ERG) may be recommended, and your pet may be referred to a veterinary ophthalmologist for the procedure. The animal is often sedated for the ERG and wears a contact lens (containing a gold electrode) that is attached to a recording device. Different-colored lights are shone into the eye, and the reaction of the retina is evaluated by a computer program. ERG abnormalities compatible with PRA (such as a decreased response to blue and white light) can be detected prior to physical changes in the retina.

Later in the disease, evidence of retinal degeneration can be seen on the eye examination.

No treatment is available for this genetic disease. Ongoing research is being performed on gene therapy for PRA. Secondary cataracts may develop from PRA, but removal of the cataract provides no benefit to the animal.

Little follow-up is needed unless secondary cataracts develop in the future. The disease is not painful and does not affect the rest of the body.

All affected animals eventually go blind. Animals with late-onset disease often go blind over a period of about 2 years.

I know this isn’t the best information to hear, but it certainly is not a diagnosis, and just information to help you. Based upon the research I did, retinal degeneation (whether it be primary or taurine caused) is most likely in a younger cat. If he were to get an ideal workup, I would certainly want his BP checked, as well as intraocular pressure. A visit to a specialist would really be encouraged. There are infectious diseases that can cause blindness in cats (viral, bacterial, funal, and parasitic), but I am assuming if your veterinarian tested for toxo, that he ruled out the obvious ones like FIV and FIP. I have found no studies on nearsightedness in cats—in journals or veterinary discussions. Conrad’s vision problem does indeed sound progressive and I would want him checked out by a specialist while he still has some vision remaining, in case it can be halted (such as the taurine).

Please let me know if you have any further questions, and best of luck to you and Conrad. He is very lucky to have a dedicated owner and to have been rescued by your family.

My best,

Dr. Laci

response by XXXXXXXXXXXX on 2011-10-19 15:07:02

Hi Dr. Laci,

Thanks so much for your response. To answer your questions…

1. No one ever mentioned his blood pressure, but valve insufficiency often leads to pulmonary hypertension, right? Could that affect his vision?

2. and 3. His intraocular pressure has not been checked; our vet said he could refer us to an opthalmologist, but that s/he was only likely to confirm that Conrad is nearsighted.

4. No, light does not hurt his eyes. When he is in bright light his pupils contract, and his eyes actually look normal.

5. He eats wet Best Feline Friend (mostly seafood) and dry Halo (salmon). We’ve been worried that his (and his brothers’) diet is too rich in seafood, but a couple different vets said it was fine. He is obsessed with people-food, so we occasionally give him white bread and potato products; he has no tummy problems.

Regarding his eyes: In bright light the pupils contract, and his eyes look normal. In regular light they look like burning embers; they are vacant, all pupil, and unfocused. I just had Conrad’s dad send a couple photos from his work computer, but something is wrong with my email and I can’t seem to download any attachments. I hope the description is useful.

Thanks so much,

~Julia

response by Dr. Laci Schaible on 2011-10-19 14:41:57

Hi Julia,

Thank you for the thorough history. I am going to have to do some research for you as Conrad’s case is quite unique. In the meantime, I do have a couple questions for you:

1. How is Conrad’s blood pressure?

2. Has his intraocular (eye) pressure been checked?

3. It sounds he has had an extensive work-up; has your vet talked about referral to an ophthalmologist or has he been to one?

4. Does light hurt his eyes, as in does he squint in bright light?

5. What food does he eat?

If you are interested, I’d be happy to review his medical records. That will just help me have a better idea what the vet found and which tests exactly were performed. If you want to do this, you would need to request a copy from your vet and you can fax them to me at (484) 544-8862.

Also, if you can take a picture of his face and attach it below that might help. If not, can you tell me if his eyes look normal? Obviously I can’t do an eye exam over the internet, but if they look like normal cat eyes to you is useful info.

Thanks in advance, and I will be in touch.

Best regards,

Dr. Laci

response by XXXXXXXXXXX on 2011-10-19 14:27:31

Hi,

I have three cats, all between 1- and 2-years-old. My cat Conrad is almost two, and his vision has gotten progressively worse over the last year; he is nearly blind.

When he was a kitten he was hit by a car. One of his femurs was shattered; we adopted him when he was recovering. He recovered from his injuries completely, but had a high fever a couple weeks later (right before he got his leg brace off), and was never the same. He was diagnosed with a heart murmur (mitral and tricuspid insufficiency – he takes no medication), he became less friendly and alert, and his vision began to decline. We brought him to the vet, who did a complete work-up, including cultures for several parasites (the only one I remember was Toxo) – all negative. He checked his eyes for conjunctivitis, uveitis, and other abnormalities, but saw nothing.

At this point, we suspect he is almost blind. He runs into doors and legs, and paws the air before jumping off the furniture. Most of what he seems to see is close enough for him to feel with his whiskers. We just did a test with a laser pointer – he can see it from about an inch away. His eyes have no cataracts; in regular light they are unfocused and all pupil. They look more like burning embers than eyes.

Aside from his nearsightedness, Conrad is a pretty normal kitty. He has a regular (often ferocious) appetite. He is somewhat more lethargic than his brothers, likely due to his heart condition and his difficulty seeing his playmates.

Any idea what could be wrong with him? My Internet research about cat eye health seemed to indicate that nearsightedness in cats is usually due to an underlying condition, rather than something that occurs independently, like it does in humans.

I also read something (it might have been in a forum, I don’t remember) that said that some cats have problems processing taurine, and that those cats will suffer effects of taurine deficiency if they don’t get extra supplement. Should I start giving Conrad taurine?

Thanks so much,

~Julia