dogmedgallery
Canine Encyclopedia
Feline
Encyclopedia
Links
Subscriber Area (members only)
Zoonotic disease
Becoming A Veterinarian
Becoming A Veterinarian and other stuff
Biographical Info
Help
Support Vetinfo, vetinfo4dogs
and vetinfo4cats and make a donation
Eye Problems in Cats
Retinal Atrophy
Herpes eye infection
in stray kitten
Problem
with remaining eye after one is removed
Sudden blindness
Melanosis or Melanoma in
eye
Eye problem still not
diagnosed
Sudden blindness
Non responsive
Nuclear lenticular sclerosis
Why do cats eyes glow
in the dark
Quivering eyes - nystagmus
Corneal ulcers
Color vision in cats
Blind cats
Sudden onset
blindness
Spontaneous Iris Melanosis
Eye infections
Eye wash for cat
Repeated Corneal ulcer
Chronic Conjunctivitis
Uneven pupil size
Chronic eye problem
also see Horner's Syndrome
also see Infectious Disease
also see Herpes virus infection
| Your cat's eyes are very important to them. Taking care of their eye health is just as important as taking care of your own eyes. Lasik vision correction is becoming more and more common every day. If you have problems seeing, get the facts about laser eye surgery and see if it's right for you. Your cat will be strong and healthy with the proper eye care... shouldn't you want the same for yourself? |
Question: Dr Richards
Can you tell me anything about Retinal Atrophy, and hope for some kind of
recovery? I noticed about a year ago my 13 year old male cat's pupils were
always enlarged. The vet checked and said every thing was fine, we just
went for another check up and she told me he has this. He can still see
somewhat, and doesn't have to much problem in getting around, is there
anything to prevent further deterioration?
Debbie
Answer: Debbie-
I want to get this in first before I go on, in case I forget. If this were my cat, I would be asking for referral to a veterinary ophthalmologist for confirmation of the diagnosis of retinal atrophy. I can say this with absolute certainty because I diagnosed this problem in my own dog and immediately took her to an ophthalmologist for confirmation. I did this even though I knew that there was no hope for treatment. I felt that confirming the diagnosis and knowing that I didn't make a mistake and miss a treatable condition was worthwhile.
The most common cause of retinal atrophy in cats is high blood pressure leading to retinal detachment, leading to retinal atrophy. If the high blood pressure is treated immediately there is a chance that the subsequent damage can be avoided. While I can't remember a patient who recovered after more than a week of being blind, I was at a seminar on ophthalmology that Dr. Mary Glaze spoke at last month and she said she had seen some come back after a month of blindness. If
complete blindness was present when the pupils were dilated a year ago, it isn't too likely that treatment at this time would make a difference. High blood pressure usually occurs due to kidney disease or hyperthyroidism, so it is still worth thinking about checking for these disorders and measuring blood pressure and treating any of these conditions if they are present.
Taurine deficiency used to be the most common cause of retinal degeneration in cats but once the requirement for higher taurine levels was recognized, this cause became uncommon. Unless your cat is being fed a diet low in taurine this is presently an unlikely cause of the degeneration.
Glaucoma can lead to retinal atrophy. In cats glaucoma can be a very insidious disorder. It is worth checking eye pressure to ensure that glaucoma is not present even if the retinal atrophy is complete, because glaucoma is painful. It is really surprising how much better some cats feel after treatment for glaucoma when their owners were not aware that behavioral changes they were seeing (like clinginess or crying a lot) were due to glaucoma.
Progressive retinal atrophy does occur in cats but less commonly than it occurs in dogs. It is most common in Abyssinian cats. When retinal atrophy is the problem, the usual progression of symptoms noted by the cat owner is dilated pupils > night blindness > total blindness. There is no known treatment for this disorder. Fortunately most pets who have progressive retinal atrophy adapt very well to blindness because they get to adjust to the blindness gradually and so they can learn to adapt better than a pet who becomes blind suddenly.
I hope this is helpful.
Mike Richards, DVM
10/15/2002
Michal input : Taurine deficiency can be caused by feeding a steady
diet of canned tuna because your cat likes it. There is a huge variety of
well balanced cat food available now in flavors to tempt even the pickiest cat
Herpes
eye infection in stray kitten
Question: My husband found a tiny kitten in the street
and like an animal lover brought it home. We of course ended up in the animal ER.
One eye was completely matted shut, he was covered in fleas and ticks and was infested
with parasites and hook worms. Well, everything has improved
except the eye. My vet felt it probably started with an untreated respiratory infection.
The eye is now open but is many times larger than his good eye and
has to be cleaned daily to get the film and gunk off and sometimes it
bleeds. There is no pupil visible and it is a bloody looking gray. It of
course does not respond to the antibiotic. He has gained to almost 4 lb.
now and the plan is to remove the eye. Will the herpes infection continue
and infect the surgical site? I've read your other e-mails on herpes
and I'm concerned about infecting my older cat. The older cat is about 9 and was
also a stray when we found him at about 4 months of age. He has been
very ill twice with what the vet thought were respiratory infections ( don't know
if they were viral or bacterial ) in the 9 years I've had him. How
chancy is it to bring the kitten up from his basement home after the surgery?
I also trap and neuter feral cats and try to find homes for strays but I'm always
cautious about keeping them separate from my house pets. However
I am not hopeful of finding a home for a little one eyed cat and expect we will
be keeping him ourselves. That's fine because we're already attached
but I'm agonizing aver the possibility of exposing my older cat. I did take note
of a previous Q&A suggestion and have been giving the kitten l-lysine daily.
Any advice will be appreciated.
Thanks, Judy
Answer: Judy-
Once a cat is infected with herpes virus it is usually infected for
life. The virus can usually be found in the trigeminal ganglia, a nerve connection in the facial area
and can also hide in the optic nerve, the tonsils and the nasal turbinates. It is currently
estimated that greater than 90% of cats harbor this virus in their bodies, so the risk of a new infection
for your older cat is not great. There are different strains of herpes virus, though, and sometimes
exposure to a cat shedding the virus does seem to cause a recurrence of clinical signs in a cat
who has been previously
infected. The length of time that cats shed the herpes virus varies
a lot but can be as short as 2 weeks or as long as life long. It is probably reasonable to consider
allowing the cats to get to know each other, if you still intend to keep the kitten, about a month
after clinical signs of upper respiratory disease have resolved. The vaccinations for feline herpes
virus and feline calcivirus work pretty well at reducing clinical signs, even though they can't
prevent infection with the viruses. So if your older cat has been vaccinated within the last 1
to 3 years the risk of a serious
illness from one of these viruses is reduced significantly by that
protection. Herpes virus is pretty easy to kill and doesn't live long in the environment. Calicivirus
lives longer and is not susceptible to all disinfectants but is killed by dilute chlorine bleach
solution (1:30 dilution), so treating surfaces where you can is also helpful in reducing the chances
for infection.
Hopefully, the kitten has done well. Many people aren't adverse to owning a one-eyed cat, especially if they have seen it and realize that it isn't a terrible cosmetic defect, so I think there is hope for finding him a home, although he has found a good one already.
Mike Richards, DVM
8/13/2001
Problem
with remaining eye after one eye removed
Question: Hi, Dr. Richards,
Hope you had a wonderful Christmas and that 2001 will be super for you!
Just wanted to run something about Splotchy's Remaining Eye -
it seems to be continually dilated. When I compare her eye to my other cats' eyes - even when they are
outside in the back porch where there is more light - her left eye pupil looks completely dilated. I've noticed
her almost bumping into other cats or objects, so I'm wondering if she's lost some of her vision in that eye with
all that took place with the other eye we had removed. Is that possible? There's no swelling,
and her area where they sewed together her other eyelids
looks like it's healing fine. Appreciate any advice you
can give.
Answer: Cecilia-
The optic nerves from each eye run to a common site. There are times when damage to one optic nerve is significant enough to spread to this connection and result in blindness, or partial blindness, in the opposite eye. This may have happened. Some cats will recover from this condition if it is just post-surgical inflammation but it may be permanent. Cats usually adjust pretty well to being blind, so if this is a permanent change hopefully it will be possible for Splotchy to adjust and have a nearly normal life.
Mike Richards, DVM
1/8/2001
Sudden blindness
in Persian cat
Question: Dr. Richards,
I have a 13 year old female Persian cat. While I was in Europe,
she
seemingly went blind overnight - as a matter of fact, probably the
day I
returned. I immediately took her to the vet who only looked at
her pupils
not responding and said she was suffering from optic neuritis.
We tried
some steroids (I think) to reduce swelling for 10 days but it seemingly
made
no difference. Then, a few days after she stopped the medication,
she
started walking around in circles for hours on end. I took her
back to my
vet who said that it might be a neurological condition related to the
optic
neuritis and gave her a few shots to reduce swelling plus amiltryptilene
(I
think it's called) to calm her down. He also noticed that her left
pupil was
dilating where it had not been responsive before. It has stopped the
circling for hours, but she still does it quite a lot. She's
constantly
hungry. The other thing she's started doing that has me worried
is that
sometimes when she's still, she turns her head repeatedly from right
to left
like she's tracking something. Does this sound like it's all
related to
optic neuritis, or could something else be going on?
Paula
Answer: Paula-
The most common cause of sudden blindness in older cats is probably
hypertension (high blood pressure), usually associated with
hyperthyroidism, kidney disease, diabetes or some other systemic illness.
Optic neuritis does occur independently of hypertension. In addition,
glaucoma can cause blindness that seems to have a sudden onset, even
though
it has quietly been causing damage for some time. This is actually
one of
the causes of optic neuritis. Cats do not get glaucoma as often as
dogs do,
but it is something else to consider.
Many vets (including us) do not have an in-clinic method of measuring
blood
pressure. In that situation, I think that it is reasonable to use
medications to control blood pressure on the presumption that it might
be
the problem, until it is clear that it is, or is not, part of the problem.
We use amlodipine (Norvasc Rx), usually 1/4 of a 2.5mg tablet once
a day.
Mike Richards, DVM
10/14/2000
Question: I have a 2 year old Persian who has melanosis of the
iris in her left eye. I did read your synopsis of
this condition and then took her to see a veterinary
opthamologist at the animal hospital in NYC. I was
told that the clinical diagnosis of no cancer was
being made based on the fact that the "freckles" in
Jules' eye were flat, light colored and not extending
to the furthest most points.
The doctor said that I should keep an eye on it( no
pun intended) and bring Jules back in a year for a
re-exam; however, I would like to know if you think
that this approach is too laid back and a second
opinion should be sought. Also, can I do anything
nutritionally or otherwise to ward off a full blown
melanoma or is it inevitable?
Jules weighs 8 lbs. and is in good health and fully
vaccinated. I discovered the freckles about 4 ir 5
months ago when he turned two.
Ellen
Answer: Ellen-
Dark color changes in the iris are not always due to melanoma but it
is
important to continue to watch carefully for changes in the iris,
especially anything that appears to be an increase in thickness. The
ophthalmologist has the best ability to evaluate these changes, so
I do
think it is reasonable to trust his or her opinion. Between examinations
at
the ophthalmologist's, you can check the eye once a month or so to
be sure
that there freckles are staying flat and becoming a thickened spot
or
visible tumor on the iris.
I do not know of anything that is known to prevent the occurrence of
melanomas affecting the inside of the eye nor anything that works to
stop
the growth of the tumor once it starts. In cats, about 60% of melanomas
of
the eye are malignant and removal of the eye is recommended when there
is
some certainty that a tumor is present.
We do see pigmentary changes that never develop into a problem and the
ophthalmologist probably has a much better feel for which ones will
be a
problem and which ones won't than general practice vets, such as my
wife and I.
Mike Richards, DVM
10/6/2000
Eye problems still not diagnosed
Question: Dear Mike,
Thanks for your reply regarding my Dylan's eye problems. I wish
I could
have replied sooner -- my computer is down for the near future, I'm
writing this from the library. It gives me some perspective to
know that
you also send your putative herpes infections to an
opthalmologist. Dylan's herpes test was negative, thank goodness,
but
that still leaves us in the dark as to what it IS.
Now I have a second cat with the same syndrome: she had a fever and
didn't
eat for 3 days, then one eye swells up, the conjunciva and upper lid
swollen shut and out about half an inch -- almost as if she'd been
stung
there, by a bee. Today it's looking slightly better. I
think it will now
become a chronic situation, where it flares up and oozes a yellowy
mucous
substance, then clears up for a month or two. I don't see anything
like
this in my vet handbook, does it ring any bells with you?
Thanks as always.
Laura
Answer: Laura-
Eosinophilic granuloma complex will sometimes produce symptoms like
you are
seeing. It can even sometimes occur on the cornea itself and it looks
a lot
like herpes virus infection when this happens. Often, cats who have
this
problem affecting their eyelids or corneas also have eosinophilic lesions
elsewhere on their skin or in their oral cavity. It might be worth
checking
carefully for other signs of skin disease.
Allergic conjunctivitis is supposed to be pretty rare in cats, but it
is a
conceivable problem.
I have read recently that the false positive rate for PCR herpes tests
is
thought to be higher than initially reported (about 10% false negative
in
initial studies), but I haven't been able to find a recent report that
gives sensitivity and specificity information for PCR testing. I hope
to be
able to find this information because I have been relying on these
test
results, too.
Mike Richards, DVM
8/10/2000
Sudden Blindness and vestibular syndrome
Question: Momcat has a diabetic14-year-old grandson. Bear's
diabetes was diagnosed a year ago at same time one eye had to be surgically
removed. He began developing a cataract in remaining eye first of this year. The
end of March his daily insulin was lowered to 2 units from 4. Two weeks later
he had what appeared to us to be a stroke and became totally blind. He was
checked for any number of conditions, all results being negative. Most
likely diagnosis seemed to be idiopathic neuropathy, as he gradually began showing signs
of recovery. His eye doctor, however, had another theory: vertiginous
activity.
Are those two conditions one and the same?
Answer: I don't recognize the term vertiginous activity and got side-tracked while looking for
information on this. My best guess is that it means the dictionary
definition of vertiginous (having to do with vertigo, or loss of balance)
and activity -- so, activity related to loss of balance. That doesn't
tell
me enough to relay any information though.
The most common cause of sudden blindness in older cats is high blood
pressure. This is more likely if diabetes, hyperthyroidism or kidney
failure are present. Since you say that many tests were run, I have
to
assume this was checked for, though. Other signs that people
commonly
associate with strokes, such as balance loss and weakness can be due
to
peripheral (sometimes referred to as idiopathic) vestibular syndrome,
which
might be another name for the condition that either of the vets was
referring to. Cats normally recover from this condition although often
more
slowly than dogs do. I don't usually associate blindness with this
problem,
though.
.I wish I could help more with the question about Bear.
Mike Richards, DVM
7/9/2000
Question: Dear Dr Mike,
My 3 year old cat Dylan had a case of conjunctivitus in January, which
didn't
respond to a triple-antibiotic opthalmic ointment (Neomycin, Bacitracin?,
and
something else, altho I was not very diligent about it -- possibly
the reason
why). It had started in one eye and moved to the other, like
chlamydia. In
May or so, he still had the problem which would flare up and then clear
up
slightly, red and swollen conjunctiva, tearing and puss-y discharge,
no
apparent pain.
Another vet took a swab and looking at it under the microscope said
there was
evidence of mycoplasma, and gave me an ointment called Chloramphenocol,
saying that there was a possibility that he might be allergic to it.
I
wondered if he might be allergic, as the redness and swelling looked
worse
after a few days of use altho the puss-yness would improve.
Eventually it seemed as if it was gone (still, I was not very diligent,
I was
supposed to dose him 4x/day, and he is out most of the time, and also
would
run from me when I wanted to dose him).
Anyway, a week ago, it seemed to return. We took him to the vet,
hoping to
get some medicine that he wouldn't be allergic to (and that would clear
it up
instantly, if possible!), and a swab was taken for an outside cytology,
which
will take 2 weeks. In the meantime I was given Gentocin drops
(3x) and will
give an oral antibiotic (Clavamox, 2x) for some upper respiratory congestion
that is new with this infection. His nose isn't runny, and his
lungs are
clear, it seems to be in his throat -- he coughs or sort of chokes,
occasionally, and swallows hard). Also, I had noticed that the
affected eye
seemed cloudier, differently reflective when seen in the right light,
but the
vet didn't have anything to say about that, it may have been that I'd
just
put ointment in that eye. They checked for injury to the cornea.
Last night, after the vet appt, and this morning, I notice that the
affected
eye's pupil is completely enlarged, the conjunctivi are still inflamed
and
swollen. The vet (not the one who saw him, who will not be in
again for over
a week) said that there was no record of having put a relaxant in his
eye,
and that it might mean that there is pain in the eye... that it was
not a
reason for panic, and that "if the eye looks worse" in a couple of
days, I
should stop the Gentocin.
After consulting your site, I'm concerned that Gentocin is unlikely
to help
in spite of the struggle and strain we will have with compliance, and
I'm
concerned that it may be hurting him. Is his eye "better" if
the redness and
puss-yness subside, but the iris is enlarged? Is he temporarily
blinded in
that eye? Does it seem likely that he has a herpes rhinotracheitus
virus?
Will he be blinded? I will call the vet and confirm that the
tests they're
doing will give a definite diagnosis if herpes is hard to catch --
I was told
that it will report whatever they see on the swab.
What about the dangers of infection for my 2 kittens, their mom and
my
16-year old diabetic cat?
Please give me your thoughts -- I'm concerned about all this, and now
the
only vet that has seen him is out of touch for present. I hope
I'm not
forcing you to repeat what is already on your site, I looked pretty
carefully. I know you can't diagnose him, but could you expand
upon the
enlarged pupil (would an antibiotic cause this? or the fluorescent
green
stuff they put in his eye?), and the infectiousness to my other cats?
Thanks. Laura
Answer: Laura-
In almost any situation in which conjunctivitis occurs in cats, the
most
likely diagnosis is feline herpes virus 1 infection, because it probably
accounts for 80 to 90% (or even more) of conjunctivitis problems in
cats.
This is particularly true if the cornea shows signs of cloudiness or
blood
vessel growth (red vessels visible in the cornea that often have a
sort of
"lightening streak" appearance).
The pupil enlarging on this side is a little strange. Atropine eye drops
will make the pupil enlarge, so checking to be sure that you have the
right
drops might be a good idea. Another possibility is that Horner's syndrome
is occurring. In this disease, the eye with the enlarged pupil is the
normal eye and it only looks odd because the other pupil is constricted
so
much. Horner's syndrome occurs spontaneously in cats and it can also
occur
as the result of neck injury, masses (tumors) in the chest or damage
to the
affected eye. The most common form in cats is probably the spontaneous
form
and it usually clears up on its own.
There is a pretty good chance that the Gentocin (Rx) drops are not going
to
be helpful but that is true of any antibiotic drop used when herpes
virus
is present. It may help prevent secondary bacterial invasion of the
cornea.
Viral conjunctivitis is hard to treat. It is possible to use an anti-viral
drop but they usually have to be formulated by a compounding pharmacist.
Our experience with anti-viral drops has been mediocre. They sometimes
do
seem to help but not always.
Herpes virus is so prevalent in cats that the risk of causing a new
infection in your other cats is low. Not because the virus doesn't
spread
well to other cats but because it does spread so easily that most cats
have
been exposed by the time they are a few months old. If one of your
cats was
not exposed they would be at risk for infection and probably will get
infected. The immunity to chlyamidiosis is pretty short-lived, so one
sign
that this was your problem would be infection in the other cats. It
can
take specialized testing to be sure whether or not herpes virus is
present.
Our patients usually only get tested when the conjunctivitis or corneal
disease is severe and persistent, prompting a visit to an ophthalmology
specialist but it is possible for any veterinary practice to obtain
the
samples and send them in for testing.
My guess is that you other cats will probably be OK. There are other
causes
of conjunctivitis in cats but herpes virus is the most common and
chlamydiosis is probably second. Allergic conjunctivitis occurs
occasionally and tear film deficiencies or defects sometimes cause
problems, too.
Good luck with this.
Mike Richards, DVM
7/16/2000
Question: I had a question about Neuclear Ventricullar Sclorosis.
Marsha
Answer: Marsha-
I am not familiar with the term nuclear ventricular sclerosis.
There is a
condition referred to as nuclear lenticular sclerosis, which affect
the
eyes of pets and I have seen the term ventricular sclerosis used to
describe scarring associated with heart muscle damage, though.
I suspect you are looking for information on nuclear sclerosis of the
lens
of the eye, though. This is a normal age related change that occurs
in the
lens of the eye. At about 8 years of age in dogs and about 10 years
of age
in cats it is usually possible to see cloudiness in the lens of the
eye and
the reflection from the eye may change from green (or red) to a hazy
blue
color. This happens because the lens is a very special tissue. In order
to
be clear so that light can pass through it, the cells in the lens have
be
oriented just right and there can not be a blood supply -- or you would
see
red all the time. The lens adds new cells from the edges, making the
center
cells get more compact as time goes on. Eventually they become compact
enough that cloudiness occurs. This would be more of a problem if dogs
had
to read or if they were strongly dependent on central vision but they
don't
read and they don't lose the ability to see movement which is more
of a
peripheral vision ability. So most dogs with lenticular nuclear sclerosis
will continue to see well enough to get around for the remainder of
their
lives. The same is true for cats, although we do have a few cat patients
who live long enough that this change does eventually seem to affect
their
vision some. When I am not sure if a problem is a cataract or nuclear
sclerosis I send the patient to an ophthalmologist but this doesn't
happen
very often.
Hope this helps some. If this reply is way off the mark and you are
looking
for information on an entirely different condition that I don't know
about
I'll be glad to look into it for you.
Mike Richards, DVM
6/30/2000
Why do cats eyes glow in the dark
Question: Can you tell me why cat's eyes glow in the dark.
Thank you for your help.
Stephanie
Answer: Stephanie-
Cat eyes don't actually glow in the dark. They do appear to be bright
green, most of the time, when they reflect light from another source.
A way
of thinking about this is to imagine a mirror. It doesn't glow in the
dark,
either -- but if you shine a light on it, the light is reflected back
to
you and you see it as a light coming from the mirror. Reflectors
like you
see at the end of driveways or on bicycles are another example of something
that doesn't actually glow in the dark but that shines brightly when
it
reflects light.
If you go into a dark room without a light and look for your cat, you
can't
find it by looking for its eyes. This proves that they don't have glow
all
their own. It is pretty easy to find a cat in a dark room with a
flashlight, though. Even if you can't see the cat very well, you can
see
the reflection from its eyes.
The portion of the cat's eyes that reflects light is the retina, or
more
specifically, the tapetum of the retina. Most cats have green tapetal
reflections because they have colored retinas. Many Siamese cats do
not
have pigmented (colored) retinas. When light shines in their eyes,
the
reflection is red, because you see the blood vessels in the retina
instead
of the green color that hides the blood vessels in other cats.
The advantage of having reflective retinas is that light that hits the
retina passes through the rods and cones (the part of the eye that
allow
vision to occur) first. Some of it is absorbed and processed so that
the
cat can see. The rest passes into the cells behind the eye. The reflective
layer in a cats eye reflects the light that would have been lost in
this
manner back through the rods and cones, giving the cat a second opportunity
to use the light to see. This helps cats to see better in the dark
than
animals that don't have a reflective tapetum.
I don't know for sure, but I think that people must not have
much color
in their retinas, which is probably what produces the "red eye" in
photographs.
Some dogs have blue tapetums and so their eyes appear to have a blue
reflection when light shines on them.
I am not sure what the function of the different colors in the retina
really is. I will try to see if I can find some information on this
for you.
I don't have any photographs that show the green reflection except in
textbooks.
I hope this helps you a little.
Mike Richards, DVM
2/10/2000
Q: Dear Dr. Richards:
I am a subscriber and have a question about Shadow's eyes. He
is a
wonderful neutered Showshoe kitty about 1.5 years old (he was found
after being abandoned for over a month and I was fortunate enough to
adopt him). Except for his chronic (but getting slightly better)
gingivitis which you have already answered my question about, he is
very
healthy and happy. His beautiful blue eyes are a little smaller
than
usual and are slightly crossed, and they quiver(!) very rapidly.
Whenever I look into his eyes his irises are in constant rapid motion.
Our veterinarian has thoroughly examined Shadow's eyes and said they
are
otherwise fine, but she had never seen an other quivering cat's eyes.
Could you please explain why Shadow's eyes are quivering, and if there
might be any potential side effects or problems with time?
Thank you very much for your help and for all of the information you
share through your website and the VetInfo Digest.
Sincerely,
L & Shadow
A: L
I have to admit that I am not familiar with the breed Showshoe. Some
members of the oriental breeds have a congenital problem with nystagmus,
which is rapid movement of the eye, usually side to side (can
be up and
down or rotational, though). This is most common in Siamese cats but
I have
seen it in other oriental breeds on a couple of occasions. We have
a boxer
in our practice who also has this problem.
This doesn't usually cause any problems that are discernible, which
always
amazes me.
Mike Richards, DVM
9/7/99
Q: My cat has a corneal ulcer. How long will it take to heal?
A: Most of the time corneal ulcers heal with
antibiotic eye drops within 3
to 5 days. If this problem has persisted longer than that, please
let me
Mike Richards,DVM
Q: About my cat's eye ulcer --- As
you have said, most corneal ulcers probably
heal within 3 to 5 days with antibiotic treatment.....However, poor
little Tigby is
now into this for 18 days!!! My vet has chosen Neobacimyx QID,
and atropine
sulfate BID. He went in for a re-check, and had his sutures for
the 3rd eyelid
removed.....he's doing better, but not that much. His eye is
still very
much dialated from the atropine (which I've stopped), and I'm still
using
the antibiotic on a QID basis. What else, if anything can I do
to help him
along....He's still having trouble with the eye, and I'm not altogether
sure that this vet is doing all that can be done for Tigby. You
mentioned
something about more information about difficult ulcers.....it very
much
appears that this one is VERY DIFFICULT!!!!
Thanks S
A: S-
Persistent corneal ulcers in cats are usually due to herpes virus. In
these
ulcers, antibiotic drops are not helpful except to prevent secondary
bacterial infection. Atropine sometimes makes the eye feel a little
better
by relaxing the muscles that may spasm due to ocular pain but has no
direct
healing benefit that I am aware of.
It is necessary to use antiviral medications in some cats to get these
ulcers to heal and it can be helpful to use l-lysine supplementation
(this
is a food supplement). Some ophthalmologists think that debriding the
ulcer
edges is helpful and there is some disagreement about what the best
topical
anti-viral ophthalmic preparation is.
I tend to refer these cases to a veterinary ophthalmologist in my area
because this is an easy option for me, but it is possible for
most general
practices to write prescriptions for anti-viral eye drops or to use
very
dilute povidone iodine to treat these eyes. Interferon is reported
to help
sometimes (orally and/or topically) and oral acyclovir has been reported
to
help in severe cases.
There are cats who are treated with several anti-viral agents who do
not
respond to treatment. This can be a very frustrating disorder to treat.
Once in a while we see a case of eosinophilic keratitis in a cat that
really
looks like it has caused a corneal ulcer (or is a corneal ulcer). This
is
treated differently than persistent ulcers due to herpes virus. In
these
cats, corticosteroids are necessary to resolve the problem. It is obviously
very important to distinguish between the two types of problems. Corneal
scrapings submitted for cytologic exam by a pathologist is a good way
to
distinguish between eosinophilic keratitis and ulcers from herpes,
if there
is any question of this.
Lots of places in the country now have veterinary ophthalmologists on
at
least a visiting basis, so it may be worthwhile to ask your vet for
a referral.
Good luck with this.
Mike Richards, DVM
9/1/99
Q: i am looking for information on whether cats are color blind or not. i am looking for this for a science project. i need some ideas on how to prove this or disprove this. do you have any suggestions or publications that i may be able to research this topic?
thank you for your help
A: m-
At present veterinary ophthalmologists believe that cats can see color but not in the same way that humans do. It is believed that they probably lack the ability to see red well, making their vision sort of a blue/green/yellow blend. Definitely answering the question of whether or not they can see color is pretty hard since it is not possible to ask a cat what it sees.
This is going to be a very hard science project to do successfully. My honest best advice is to find another topic. However, if you wish to pursue research on this topic there are several sources of information you might wish to find. We have color vision information on our site from an article relating to dogs but the authors stated that cats had similar visual abilities, I think. The article is from the Dec. 15, 1995 or 1996 Journal of the American Veterinary Medical Association. Your vet might have it or you may be able to get a reprint by visiting the AVMA site (www.avma.org --- I think). There are other some other articles in the veterinary literature but I think this is the best one I have seen.
To determine if the cats can see color you have to have a cat who will respond predictably in a certain way to a stimulus (so you have to teach your cat to sit when offered food or to do something similar). Then you have to teach it to perform that behavior in response to a particular color and then present it with choices of color and evaluate its ability to perform the behavior at the site of the proper color - usually by only rewarding it when it sits in front of the right color. Then by evaluating how often the cat gets the "right" answer, you can determine if it can distinguish color. This is obviously a little difficult with cats who are not known for being highly cooperative in situations like that. You also have to be sure that the cat doesn't get any clues from hearing, smell, touch or taste from the experimental equipment. To really do this experiment well you also have to adjust the color intensities so that the cat couldn't be distinguishing shades of gray in black and white vision. Also, since it is recognized that cats don't see all colors that humans can see you could use a color that will throw off the results (like red) unless you check for several colors in the color spectrum.
If you're up for a lot of work, good luck with this project. If not, think about talking to your science teacher about a new topic. In any case, I hope you have good success with your project.
Mike Richards, DVM
Q: Dr. Mike: Several months ago, I started a community project to spay and release feral cats in my area. As a result, I receive lots of calls that are cat-related, but not specific to my program. Recently an area resident found and adopted a feral kitten born without eyes at her place of employment. She does not want to euthanasia the kitten. We are trying to locate information about long-term care for cats which are blind. Do you have suggestions or a list of sources which might help us with this kitten? Janet
A: I do not have any reference sources to offer. However, I do not think that this kitten will have many problems if it is a house cat. We have several blind patients in our practice at any time and I suspect that most veterinary hospitals do. Pets that are congenitally blind or who experience blindness after a chronic degenerative process tend not to be particularly bothered by their condition. As long as your friend keeps the furniture in approximately the same places and the litterpans, food and water bowls and other of life's necessities in the same places the kitten will probably do fine.
I wish your friend the best of luck with this situation.
Mike Richards, DVM
Sudden
onset blindness due to hypertension
Q: Though my cat of ten years has always been aloof, we just noticed this morning that her eyes were completely dialated even though sunlight in the room was ample. After watching her bump into things and attempt to jump through her cat door even though the door itself was wide open, I realized there was something seriously wrong with her sight. I took her to an emergency vet last night and she, before getting to the eyes, detected a heart murmur. Upon examining her eyes the vet stated that the retinas were detached, obviously due to high blood pressure (though b.p. wasn't taken) since that's the overwhelming reason for such a sudden condition (the cat was seeing fine only 36 hours or so earlier). Since the cat had been losing weight over the last 7 months (even though it ate consistently and didn't have diarrhea and very little vomiting), the vet suspected the cause of the high blood pressure was a thyroid problem; thereby explaining weight loss due to increased metabolism. I got her on Diltiazem last night to relieve the blood pressure in the hopes that maybe her retinas may some how attach again and she could regain sight. She couldn't have lost her sight more than a day or two ago. The vet said I'll know the outcome within 72 hours, though she was very concrete on what the odds are. I'm very concerned and upset at this out-of-the -blue development. What are the chances of her regaining sight? How frequent is the regaining of sight in similar circumstances? What will her quality of life be if she doesn't? What is a good plan of action in checking her thyroid, heart, and blood to see if some other organs may be having trouble? It's so surreal and hard to fathom that an animal so full of life at one instant could suddenly go irreversibly blind the next morning. You're advice would greatly help.
A: MrR- Sudden onset blindness due to hypertension is a well recognized syndrome in cats. It can occur due to kidney failure or hyperthyroidism. If treatment is started within a day or so of onset there is a 50% chance of vision being regained according to Dr. Norsworthy, writing in the June 1996 Vet Forum magazine. He recommended using amlodipine (Norvasc Rx) for treatment. Diltiazem has a similar method of action (I am pretty sure both drugs are calcium channel blockers) so it may work as well. Your vet may have access to information on this that I do not.
Hyperthyroidism is usually easy to test for. Most affected cats have high thyroxine (T4) levels in their bloodstreams. Some cats have this disorder despite normal T4 levels, though. In these cases, a T3 suppression test may be able to differentiate between affected cats and those whose T4 levels really are "normal". It is always wise to run a complete blood panel when checking for hyperthyroidism since it affects other organs, including the kidneys.
Blind cats usually do fine. The sudden blindness is a problem as it doesn't allow much adjustment time for the cat but usually they adapt well, anyway. I can only remember one or two pets in the 18 years I have been practicing who really had great difficulty adjusting to blindness. Of course, some things do have to change. Outdoor cats need to become indoor cats and it isn't a good idea to rearrange the furniture frequently. Put food bowls in the same place everyday. Make sure litterpans are easily accessible and in low traffic areas so they aren't likely to be blocked by anything your cat could bump into.
I hope all works out well.
Mike Richards, DVM
Q: Dr. Mike: My 1 1/2 year old cat (DSH; great health) has been diagnosed with iris melonosis. It looks like freckles on his iris. The vet told me it was not serious or threatening. I can not find any information on this, either through books/journals or the web. Can you tell me more about this, or direct me to a journal article regarding this condition? My cat can see fine and does not appear to have any trouble finding anything; he does not *bump* into anything or miss jumps (for example). Thanks so much, Annette
A: Annette- I can not find any information relating to the cause of spontaneous iris melanosis in cats, either. This is usually a condition affecting one (but may affect both) eyes of cats. It starts out as small pigmented areas on the iris that eventually spread and cover the whole iris or large portions of it. Due to the possibility of iris pigmentation from uveitis and from melanoma (cancer) it is important to have your vet check the eye periodically. It is usually OK just to make sure this gets done on the yearly physical exam visits but if there are any obvious changes like a visible tumor (a lump or noticeable thickening of the iris) or clouding of the eye it is best to get it checked immediately.
Mike Richards, DVM
Q: Dear Dr Mike, My male desexed cat of age 7 has had an allergy in his eyes now now and then. I have had my Vet come and tend to him and he has had a course of treatments. The third eye lid becomes so swollen,itchy, runnny and red. He is in a lot of discomfort. My vet can not work out the cause he seems to think it may be linked to an Allergy. I live in a unit with a balcony with plants - now I have 2 Jasmin Potatoe vines, 1 Norlfolk Pine tree, 3 Madonna Lillys, 1 Boston Fern, 1 Umberella tree, 1 Asparagus Fern and 2 Golden Canes. Now some of the plants are new and my cat has had this problem beofre the new plants; however, I have grown my cat a tub of Wheat Grass, he loves the grass and is always chewing it. Is it possible that this is the cause. He puts his face right into the pot to chew on the grass what if it accidently goes into his eye either one and causes an alergy or would it be the scratching onto the eye that causes the irritation, but why so severe. He had to have cortazone zone injections to ease the pain. Please help me I am at a loss nobody seems to know if it is so. A gardiner actually said this may be so. The allergy did seem to come after the Wheat Grass was grown for him. If this is so can you please suggest to me what else can I grow for him which is just as nutritious and safe. One more thing I burn scent oils usually lavendar, rose, frangapenny etc.. could they cause eye irritations. Thankfully yours
A: Allergies can occur in cats and it is possible that an allergy is the problem. Allergy testing can be done in cats but is usually done by veterinary allergists or dermatologists (at least here in the U.S.) because keeping the necessary allergenic compounds to test with is usually too expensive. There may be more accessibility to allergy testing in city veterinary practices since they have larger caseloads.
By far the most common cause of recurrent or , including conjunctivitis, in cats, is feline herpesvirus infection. Many vets find themselves treating chronic conjunctivitis without any success and often are reluctant to consider herpesvirus. I can't tell you why that is except that everyone likes to find something they can treat and herpes is hard to treat. It sometimes responds to l-lysine administration (250 to 500mg once a day). If anti-viral eye drops are available in Australia they can be very helpful. It is worth asking your vet about this possibility.
Mike Richards, DVM
Q: Dear Dr Mike, Is a very dilute solution of Boracic Acid [NOT BORIC](1 teaspoon to about a pint/half litre) useful as an eye-bath for relieving low level eye irritations in cats? As you probably know it is the basis of many 'human' eye baths, but many things don't transfer from humans to cats. I ask this because cats do get many minor eye problems, and I have concerns about continuosly administering creams with antibiotics and cortisone....I notice that there are many 'eye' questions being asked, and just wondered if this might be a useful general first-aid, symptom relieving measure? Thanks for all your info and responses! W.
A: All of the texts I have refer to boric acid solutions, which have been used for their antibacterial effect in humans and in dogs. In dogs, repeated use is reported to lead to sensitivity to the boric acid solution and eye inflammation. I have not seen any reference to the use of boric acid solutions in cats and do not know if there is a similar problem in them.
One current theory is that most of the conjunctivitis, red-eye type problems in cats are caused by chronic herpesvirus infection. The rhinotracheitis virus of cats is a herpesvirus. It may be helpful to use l-lysine orally in cats with chronic eye problems due to this, as it interferes with virus replication. When eye medications are necessary anti-viral drops may be more effective if they are available to you. If not, using an antibiotic drop or ointment containing tetracylcine may help since the other common cause of eye irritation in cats is chlamydidosis, which responds best to tetracylcines.
Mike Richards, DVM
Repeated corneal ulcers
Q: We have an Exotic Long Hair, five years old who now has had 3 episodes of corneal ulcers. No history of trauma has been noted. Each time the vet has treated him with Chloramphenicol eye drops, for secondary Infection. The ulcers are singular and sheet-like across the cornea and always unilateral. What could their origin be and is there anything we can do to prevent them? Thank you very much
A: By far the most common cause of recurrent or difficult to cure corneal ulcers in cats is chronic herpes virus infection.
It can be helpful to use l-lysine at 250 to 500mg/day to help control this problem. It can be purchased at health food type stores, usually.
If your vet knows a source of anti-viral eye drops (I think they are hard to get right now but haven't had to treat for this recently so I am not sure), they can be helpful, too.
It is possible to do punctuate keratotomy surgery for stubborn ulcers in cats. This is a fairly simple procedure but if your vet hasn't done this before he or she may want to send you to a veterinary ophthalmologist for the procedure.
That may be a good idea, anyway, given the difficulty in clearing up this ulcer. These are frustrating and the ophthalmologist may not be able to help much more than your local vet but at least you'd get a second opinion.
Mike Richards, DVM
Q: Our (domestic shorthair) cat is just a few months short of seventeen years old. She has always had very good health. She seemed to have a little poorer eyesite and/or agility lately - which would be expected for her age. However, in the last day, she seems to have developed a severe problem with her eyesite and doesn't seem to be seeing very well. I'd like to know the possible significance of the fact that she seems to have what we call her "night eyes" on all the time. In other words, her eyes are large and glassy without any pupil being discernable where it would normally be - just like her eyes would get when see wants to go outside at night. One eye subsided to its normal state for about a half hour and she seemed to see better. However, the eye reverted to the "night eye" state after awhile. Is there anything we can do to help her get her normal eyes back - until we can get her to the vet? What can we expect to be confronted with when we get to the vet? What types of things might cause this at her age? Is there any chance that something as simple as eye drops might solve the problem or should we be prepared for something more serious? Any help would be greatly appreciated.
A: It isn't possible to diagnose much over the computer and there are many causes of blindness in older animals so I wouldn't even know where to start with a list, except that the "large and glassy" appearance you describe makes me wonder about glaucoma.
Your vet will examine the eye and may perform several tests to determine what is going on. A tonemetry test measures ocular pressure and can help rule out (or rule in) glaucoma. Examination of the lens and retina with an ophthalmoscope, sometimes after dilation of the pupil (if your cat's pupils do respond to light this will probably be necessary). Sometimes more systemic testing is necessary to rule out generalized conditions causing secondary effects in the eye.
The best thing you can do is go for an exam and start the process of getting a diagnosis.
Good luck with this.
Mike Richards, DVM
Chronic Conjunctivitis in Oriental Shorthair
Q: I have an oriental shorthair cat who had a bout of conjunctivitis when I first got her about five years ago. Since then she's had occasional problems with the same eye--running, redness, it seems to bother her--and for the most part it clears itself up. Our regular vet doesn't want to keep medicating her for it because it's not serious and he doesn't want her building a resistence to the medication. My question is, is there anything I can do at home to help ease the discomfort for her? I know it will probably go away in a day or two and if not I can always get her to the vet, but in the meantime it bothers me that she might be hurting. Someone told me that this breed usually has a lot of problems with their eyes (and she's white and blue eyed which I've also heard compounds the problem.) Any suggestions? Your help is greatly appreciated!
A: The most likely problem in your cat, by far, is a chronic herpes virus infection. Rhinotracheitis virus of cats is a herpes virus. It is the most common cause of persistent conjunctivitis in cats. It is probably not possible to cure this problem and keep it from recurring. Many cats seem to be more comfortable if their eyes are treated with an antibiotic eye drop to relieve infection with secondary bacterial invaders but eye drops do not cure the viral problem. Recently, it has been suggested that the administration of l-lysine may be beneficial in control and prevention of herpes virus flare-ups. I attended a seminar recently in which Dr. Nasisse of the University of Missouri veterinary school suggested this. You might want to discuss this option with your vet.
There are other possible problems but I'm pretty sure your vet has already checked for things like eyelid deformities and such, based on your letter.
Mike Richards, DVM
Q: Dear Doctor: In July, 1996, I rescued a kitten that had viral pneumonia. I don't remember if he was treated for eye infection at that time, but since then he has been to the vet approximately 5-6 times for this problem. His eye constantly drains green goop and currently I think that I see blood in the goop. I am tired of taking him in for the same re-occuring problem. Does this sound familiar? The eye drops that I have used are "Gentocin". This usually does work for about 1 week, then the same goop returns. Help!
A: I was recently at a seminar on ophthalmology. The speaker said that there was almost no use for Gentocin ophthalmic drops in a cat -- but that they are the most frequently used drop. This is probably because of the reputation of gentamycin as a potent antibiotic with a broad spectrum of activity. That is pretty true -- but it is not broad enough to affect the two most common causes of conjunctivitis in cats, which are rhinotracheitis virus infection and chlamydiosis.
Chlamydiosis usually starts as a severe conjunctivitis (pink-eye) in one eye, then spreads to the other about a week later. It can be chronic or it can re-occur frequently. It is best treated with a tetracycline ophthalmic ointment.
Rhinotracheitis is a herpes virus. Just like herpes in people, it keeps coming back. It is almost certainly the most common cause of chronic, non-responsive conjunctivitis in cats. It doesn't respond to any anti-bacterial agent because it isn't a bacteria. Anti-viral eye drops are available but may not be very effective, either. There is some evidence that administration of L-lysine is helpful in control of this condition. I am not sure how helpful. It can still be useful to use an anti-bacterial ophthalmic drop but the best recommendation is to use one that will work well against gram positive bacteria, which is gentamycin's weak area. A triple antibiotic drop with polymyxin and bacitracin may work better than gentamycin in this case. This is especially likely in a cat that had pneumonia because of the high probability of rhinotracheitis being involved in that, too. Unfortunately, if this is the problem, chronic non-responsive disease until the body can finally develop immunity for a while is not uncommon. Sometimes, nothing seems to aid this process.
It is also important to rule out eyelid abnormalities and other disorders that can lead to chronic irritation of the eye.
Your vet may be willing to refer you to a veterinary ophthalmologist for a second opinion in this case.
Good luck!
Mike Richards, DVM
Q: Dear Dr. Mike, My cat's pupils are not the same size; the left pupil appears to be larger than the right. I've heard this can have a number of explanations, one of them possibly being leukemia, although I have had him tested recently. Would you be able to tell me what some of the causes may be for different sized pupils on a cat? Thank You.
A: Uneven pupil size can occur for several reasons. An injury to the cornea of the eye with the smaller pupil is possible. Uveitis (inflammation of the eye) can cause the pupil in the affected eye to be smaller. Horner's syndrome is a neurologic disorder that makes the pupil of the affected eye smaller. Feline leukemia can cause pupillary spasms, also resulting in a difference in size of the pupils. Central nervous system injury can lead to difference is pupil size and in this case, the eye with the larger pupil is often the affected one.
A corneal ulcer often causes the cat to hold the eye partially shut. The normally clear cornea may be gray where the injury is, but it may remain clear. Some cats will avoid light when they have corneal ulcers. In many instances it is necessary to instill fluoroscein dye in the eye to make a corneal ulcer show up. The dye sticks to the damaged area. Anytime you suspect a corneal ulcer, the eye should be examined as quickly as possible.
Feline leukemia may affect the pupil size without any other visible disease or there may be signs of lethargy, depression, inappetance or signs of a generalized illness.
In Horner's syndrome, the third eyelid is usually at least partially visible in the affected eye and often covers 1/3rd to 1/2 of the eye. The eye may appear to be sunken into the socket. Horner's syndrome happens because there is injury to the sympathetic nerve to the eye. This can happen anywhere along the nerve's course and it courses from the brain down the neck, through the chest and back to the eye. So injury to the neck, chest or brain can lead to signs. A tumor in the chest can cause pressure on the nerve and produce signs. This syndrome also occurs in feline leukemia virus infected cats because chest tumors are more common in these cats. Horner's syndrome will sometimes appear for no apparent reason and then disappear in a few weeks. Gomez might be able to tell you what happened if he could talk -- a neck injury, bite wound or something like this are likely causes that could be easily missed.
There are probably a number of other reasons for uneven pupil size that I can't remember at the current time.
Your vet can help you distinguish between these problems. Sometimes, it is necessary to refer a patient to a veterinary ophthalmologist or neurologist for a more definitive diagnosis.
Mike Richards, DVM
Last edited 03/16/07