Greyhound eyes are wondrous things to see--they really are windows into the dog's soul. But sometimes we see things we don't expect to find there.
I'd noticed Comet rubbing his right eye, and in looking very closely at it, saw a white edge along one part of his cornea, superimposed on the edge of the white of his eye. There were also a few flecks of white that were not along the "edge." I wasn't sure I was seeing what I thought I was seeing, so I had Jack look, too. He saw it, too.
I'd never heard of pannus before it was mentioned on Greyhound-L, but armed with that information, I could look it up in "Care of the Racing Greyhound." The description there made me pretty sure what we were facing really was pannus. A trip to the vet was in order.
The vet carefully examined both Comet's eyes. She only saw the "film" in his right eye. She put something in his eye to "stain" the cornea, to make sure there was no other problem with it. She said that she wasn't aware greyhounds could get pannus--she only knew of German Shepherds and a few bull dogs. I mentioned that it probably wasn't all that unusual in greys, since it was mentioned "The Care of the Racing Greyhound," which I'd brought with me. She asked to see it (I thought she'd never ask ), and she photocopied the part on pannus. The vet told me that the other pannus cases she'd seen had been considerably further along and more obvious--Comet's was definitely caught in the beginning stages.
The vet warned me that ultraviolet light affects pannus, so the condition will likely worsen in the summertime when the sunshine is stronger, and that we should take care keep Comet from being in bright sunlight for extended periods of time. This especially becomes important in higher-altitude locations.
Comet now receives drops (Neomycin and Polymyxin B Sulfates and Dexamethasone Ophthalmic Suspension) in his eye on a daily basis. Hopefully, the treatment will diminish over time. The idea is to use the minimum amount of medication that keeps the pannus in check.
When a dog's immune system decides that the eye is foreign tissue and attacks it, you get pannus. German Shepherds seem to have a genetic predisposition to the problem, but not Greyhounds. The prevalence in Greyhounds, according to research my regular vet, Dr. Basilovac, has been doing lately, seems to relate to infection or injury as a cause. [There are some folks on Greyhound-L who cited knowing of related greyhounds who all had pannus, so they feel that it could, perhaps, be a genetic problem in some lines of Greyhounds.--slt]
The eye is a "sealed space" with its own antibodies, distinct from the rest of the body. If that immunologic isolation is compromised, the body's immune system and the eye's immune system go to war, with the eye itself as the battlefield. Pannus with gradual onset probably results from an infection compromising the immune barrier. Pannus with immediate onset probably results from injury. The classic cause of this type of pannus in humans is hitting the windshield in a car accident. Laser, my pannus dog, came with a medical history describing a dog who was fine one day and totally blind the next. He was effectively blind for two days, with pannus as the permanent outcome. Probable pannus because there is injury.
Laser seemed to be absorbing prednisone systemically from the drops he'd been on since he came last May. Since the eye specialist did not want to explore treatment options, we went back to our regular "family doctor." He has researched newer recommendations as found on Dr. Michael Zigler's page (he also contacted Dr. Zigler for details). This week, Laser was switched to custom-formulated drops containing 2% cyclosporine with a low level of dexamethasone. The dex is still a steroid, but it's just enough to offset the slight irritation cyclosporine can cause. He squints for just a moment after the drops are administered, but there has been no other adverse effect. His eyes seem noticeably better already, so here's hoping.
This following information was compiled by Praveen Mutalik and posted on Greyhound-L. His personal observations from talking to a veterinary opthalmologist are reproduced here with his permission:
My oldest greyhound, Skipper, has a slightly opaque film over his right eye. There is also some blood vessel growth over a part of the eye. We took him to a vet opthalmologist and it was diagnosed as Pannus. The treatment for it is steroid ointment in the eye to get rid of the blood vessels. Unfortunately there is no cure. We can just try to control it.
This is a relatively rare disease in Greyhounds. As a result, it often gets overlooked at a regular physical exam. You, as the owner of the dog, should draw your vet's attention to it.
There are a couple of things that need to be done prior to putting ointment (especially corticosteroids) in the eye.
a) The Vet MUST stain the eye with a dye and then wash out the dye. This is a test for active ulcers. If there are active ulcers in the eye, the dye stains these and, in a darkened room with a light shining in the dog's eye, they can be seen as colored specks. THIS IS VERY IMPORTANT. If there is a active ulcer it must be treated BEFORE the steroid treatement for Pannus is initiated. If this is not done, it could lead to blindness.
b) The vet should (Skipper's opthalmologist always does this but Kathy's vet did not) test the amount of tears in the dog's eye. The way this is done is to insert a strip of blotting paper in the eye for one minute. At the end of the minute, the length of the blotting paper that is wet is measured. If this amount is too small, artificial tears may be administered. [This test will determine if the problem is "dry eye," a condition where the eye isn't producing enough lubrication. --slt]
c) Possible medications: Initially Skipper was put on a medication called Neoperdif. This is a corticosteroid with a antibiotic. Unfortunately, Skipper was allergic to the antibiotic (pink ring around the eye). He was then switched to Ax-Dex (another corticosteroid). This worked very well and the pannus was under control. We eventually swithed over to Dexamethasone (supposed to be the same as Ax-Dex, but cheaper). His eye seems to do the best with this medication.
d) The key to the medication is frequency of application as opposed to the quantity of application. For example, let us assume that you are required to administer 1/2 inch of medication over the day. It is far better to apply this in 4 doses of 1/8 inch a day, rather than 2 doses of 1/4 inch or 1 dose of 1/2 inch.
e) Pannus cannot be cured. It can only be controlled.
f) If the corticosteroids do not work, a more expensive solution is to use the immuno-suppresent drug cyclosporine. This is the same drug that is given to human organ transplant patients. It's not sure yet how or why this works, but it will be something I ask the opthalmologist the next visit.
g) If you are prescribed corticosteroids be very conscientious of applying it. Take it from someone who has been doing this with his dog--it works.
h) As always, no matter how stupid your question may seem to you at the time ask your vet/opthalmologist the question! If you have a problem with this, remember you cannot do worse than me. If your vet does not know the answer, he/she should at least tell you that they will look it up for you.
Pannus is a sub class of Superficial Keratitis.
Superficial keratitis is common in all species and is characterized by corneal vascularization and opacification, which may be due to edema, cellular infiltrates, pigmentation or fibroplasia. If ulceration is present, pain, manifest by epiphora and blepharospasm, is an outstanding sign. Unilateral keratitis frequently is traumatic in origin. Mechanical factors, such as lid conformational defects and foreign bodies, should always be eliminated as possible causes since improvement will not occur until they are resolved. Ulcerative keratitis may be complicated by secondary invasion by bacteria, and in horses by saprophytic fungi. Bilateral superficial keratitis may be immune mediated or associated with a lack of tears, conformational defects, or infectious agents.
A specific chronic superficial keratitis (Uberreiter's disease, pannus) is a bilateral, progressive, proliferative, superficial keratitis that begins laterally at the limbus and eventually extends from all quadrants to cover the cornea. It is most common in German Shepherd Dogs. Specific therapy for superficial keratitis (SK from now on) consists of topical antibiotics, antiviral or antimycotic agents when appropriate, removal of mechanical irritants when present, tear replacement when deficient and corticosteroids when immune mediated. The latter may have to be continued indefinitely and the frequency varied depending on the response.
Interstitial Keratitis (IS) is a deep involvement of the stroma and is present with all chronic and many acute cases of anterior uvetis. The corneal neovascularization is deeper and less branching than in SK. If the endothelium has been disrupted, corneal edema is often marked. Systemic diseases such as canine hepatitis, malignant catarrhal fever, systemic mycoses and septicemias that localize in the eye, are causes for bilateral or unilateral IS. Therapy is directed at the anterior uvetis, the systemic infection or both.
Ulcerative Keratitis (UK) may be superficial, deep, deep with descemetocele, or perforating. Pain, corneal irregularity, edema, and eventually, neovascularization are signs of ulceration. A dense, white infiltrate at the ulcer margin indicates strong leukotaxis and bacterial involvement. To detect small ulcers, topical sodium fluorescein may be required. In dogs most ulcers are mechanical in origin. All ulcers have potential for secondary bacterial contamination or endogenous enzamatic "melting" of the stroma. Therapy for superficial ulcers is usually medical, and consists of topical antibiotics, topical atropine for iridocycloplegia, and correction of any mechanical factors.
These sites also contain information about pannus (some include photos or diagrams):
CIKS and Vogt-Koyanagi-Harada
Chronic Superficial Keratitis (Pannus Syndrome)
Cornea with Chronic Superficial Keratitis
Pannus (Chronic superficial keratitis)
Pannus In Greyhounds
Chronic Superficial Keratitis (Pannus)
Chronic Superficial Keratitis (Pannus)
Chronic Superficial Keratitis, in Dogs (Pannus)
Pannus: Corneal Inflammation in the German Shepherd Dog
Pannus and the Greyhound
Pannus (Chronic superficial keratitis)
Pannus (Chronic Superficial Keratitis)
German Shepherd Pannus