As the Spring season begins, a new set of ocular symptoms appear to arise along with the emergence of the bulbs. One would not necessarily think of disease as cyclical, but we all see different ailments at different times of the year. Or maybe just more of some at different times since most diseases are not restricted by time. But before we go there, a different seasonal reminder first.

The 4th Annual Nation Service Dog Eye Exam Month

For the fourth consecutive year, Merial and the American College of Veterinary Ophthalmologists have combined to provide free eye exams for any dog officially performing a service function. Whether you are the Dalmation on the fire engine, a Guiding Eye dog or drug sniffing for Homeland Security, you are entitled to a free ocular exam by a participating ACVO diplomate during the month of May. We have participated each and every year and are happy to examine your friend once you have registered through the appropriate website provided. We have made space available on Thursday afternoons throughout the month of May for this purpose. If you and your dog fulfill the criteria, go to ACVO website (www.ACVO.org) for the link to the official registration site and then call our office to set up your free exam! Additional details are provided on the website and at the Helpful Resources tab on this website. Hope to see you soon!

Conjunctivitis

Seasonal conjunctivitis is very common around this time of year and in the fall. Most of these allergies are probably related to aerosol bourne antigens related to all the blooming plants and grasses. However, many things can create allergic responses. Most dermatologists won’t commit to an allergy diagnosis before 2 years of age in a dog, however, some reactions are seen. In addition, small lymph node-like structures called follicles will become elevated and irritated as a non-specific response to low-grade, chronic irritation. We see this response in our allergic dogs, those running through the fields like the hunting breeds, secondary to diseases like dry eye, and also in youngsters as a presumed maturation issue. All of these entities present with a history of discharge as well as redness.

If discharge is grey-white, it is usually mucus indicating irritation and inflammation. Clear tear may be present of the only type of discharge in this situation as well. If it is yellow green, this suggests bacterial infection. Brown discharge is not specific for any condition and is usually related to a pigment called porphyrin that is in the tears. This is responsible for the tear staining you may see in the corner of white-haired dogs that are tearing. Treatment therefore depends on whether the problem is inflammatory, infectious or irritative in nature. Also, local problems such as ear and teeth infections can contribute to discharge and, once treated, may resolve or diminish the discharge. The upshot….an examination is warranted to help with diagosis and drug selection.

Traumatic corneal injuries

With the weather changing, our dogs are relieving their cabin fever by racing outside and sticking their faces in bushes in search of balls, squirrels and other interesting things. This indiscriminate placement of the eye in imminent danger leads to numerous traumatic injuries that may warrant our service. Corneal lacerations, foreign bodies, simple erosions and deep melting ulcers seem to spike in the spring due to this increase in activity.

Foreign Bodies

Foreign bodies can be anything that sticks to the cornea and can be a small plant seed hull to a thorn in the eye. The depth of penetration is what dictates what can be done and the prognosis after recovery. I have numerous pictures that can be unsavory of the many things that get stuck or poked into the eye. To keep things “G rated”, a small plant object is shown. This type may be flushed out or removed with a topical anesthetic. Others that may penetrate into the eye may cause the eye to leak once removed and are removed under a general anesthetic. If leakage is noted, closure or grafting could then be safely performed.

Superficial corneal foreign body

Corneal lacerations

Corneal lacerations are seen most commonly in puppy versus cat altercations, however, any sharp object or tree limb can do it. These lesions are typically linear. Depending on the angle of entry, they may be straight and even or have a flap of tissue. Again, depending on the depth and angle, these may resolve with just medical treatment like a simple scratch wound or necessitate suturing if deep and/or long. If penetration into the eye has occurred, the prognosis depends on whether the intraocular structures have been involved and if bacteria have become transfered into the eye.

Corneal erosions

The cornea can get scratched in numerous ways but what makes the difference in healing is whether infection is present. A garden variety corneal ulceration will heal from side-to-side in a few days in the presence of prophylactic topical antibiotic, an Elizabethan collar and dilating agents if needed for discomfort. If the corneal becomes inoculated with bacteria, some nasty types will produce enzymes that digest the cornea. Depending on the severity of the bug, a hole can develop in 1-2 days that can rupture the cornea. Others may digest the tissue more slowly and the ulcer will appear more sloping than cookie-cutter in appearance. Aggressive medical and surgical therapy is required in these cases with surgery typically suggested if the depth is greater than 50% in an active ulcer. Marked discomfort and yellow-green discharge are usually noted in these cases. We may talk about surgical treatment and the postoperative appearance later, but here is an example of a typical “melting” corneal ulcer.

Deep ulcer with inflammation

All for now….see you soon, and don’t forget to get your Service Dog examined!

Ok, enough already! I get it, we live here for a reason, get to enjoy all the seasons and the diversity they bring to our lives. I like to ski, go sledding with my kids, build the occasional snowman. I have lived in more temporate and more severe climates so I have a nice barometer on weather variation and I do love the activities that each season allows. But I think we all agree….enough of the white stuff already! We have got nowhere to put it!

In all seriousness, we are trying our best, like most businesses, to keep ourselves open and available through all the inclement weather while trying to keep you, your pets and ourselves safe on the roads coming and going to the clinic. We have bulldozed as much snow as we can to keep the parking lot safe only to have the recent ice put a nice layer over the top of what remains. So be careful as we sand and salt and take your time if you are coming in to see us. Everyone has been very patient being seen earlier or later than their scheduled appointment times as scheduling itself is a challenge. We will try our best to be here and ready for you!

A number of different ocular diseases will present with a “white spot on the eye” with or without associated redness, irritation or discharge. Since there is some much white on the ground, let’s talk about what can be white on your pet’s eye.

Corneal Dystrophy

A corneal dystrophy by definition is a deposit of lipid on or in the cornea that is usually bilateral (both eyes), symmetrical, non-inflammatory, unassociated with systemic disease and genetic in basis. We see this on a regular basis and is the most common diagnosis associated with the “white spot on the eye” complaint. There are a number of different breeds that develop this abnormality that have some science to support that it is genetic in basis and I am sure there are others where we presume this is the case by the appearance. Common breeds noted in this practice include the Cavalier King Charles Spaniel, Golden Retriever, Husky, Cocker Spaniel and many others. If we rule out any other reason for cholesterol deposition on the cornea, we default to this diagnosis based on appearance and history. Typically, dystrophic areas may get bigger or more dense, can occasionally fade, and usually create no observable vision compromise to the dog. All in all, this is not a serious issue for your dog. A typical appearance would be like this:

Cornea dystrophy in a 3 year old German Shepherd

Corneal Degeneration

Lipid and mineral can be deposited into the cornea as a response to local irritation, old aging change, post-inflammatory change, secondary to elevation of blood fats and other entities that change the metabolism of the corneal tissue. This may occur in either or both eyes and may or may not have a vascular response associated with the deposition. These are classified as degenerations and may warrant intervention to stablize the region and prevent ulceration or extensive vascularization. Old age degeneration is not uncommon, especially in dogs with exposed eyeballs where protection is not optimal. Mineral binders may help smooth the area as the irregular surface can cause discomfort. In a severe form, sometimes the mineral is sloughed off and a deep hole in the cornea is created that necessitates surgery to prevent the eye from rupturing.

Corneal degeneration: note the blood vessels to the mineral

Eosinophilic keratitis

This is an odd but interesting disease of the cat. The eosinophil is a type of white blood cell that we see elevated in diseases where allergy or parasites are the primary concern. Cats have a series of diseases, primarily in the skin, where the eosinophil accumulates and creates lesions. In the eye, we can see something similar where the conjunctiva or cornea, the surface tissues of the eye, become inflamed and accumulate white plaques usually associated with vessels. The surface is usually not ulcerated so discomfort is not a feature. Herpes, the most common cause of surface disease in the cat, may be concurrent or it may be its own entity. This disease is usually responsive to antiinflammatory medication and is typically controlled, not cured. The white does go away!

Eosinophilic plaques and vessels

Cataracts

Cataracts are opacities of the lens that can be very small and difficult to observe or involve the entire lens and make the pupil appear white. When the lenses are extensively involved, vision compromise may be a feature if both eyes are affected. The color of the iris will be visible around the cataract and the central region is opaque and white. I have a posting concerning all the details of cataracts and cataract surgery on this site if you think your dog has this problem or are being referred for cataract evaluation. Here is a picture of a dog with signficant cataracts.

Dense resorbing cataract in a dog

Lipid flare

Animals will commonly get inflammation inside the eye called uveitis. Uveitis is a symptom of many problems from simple trauma to cancer. Infectious diseases like the tick-bourne entities in the Northeast or fungal disease in the Midwest can manifest themselves as uveitis with a red eye and protein and/or cellular debris suspended within the fluid that bathes the front of the eye. If your pet has uveitis for any reason and also has high levels of triglycerides or cholesterol in their blood stream, these fats can leak into the eye while it is inflamed. When that occurs, presto, you have a white eye that can look pretty scary. This is not too common, but we will see it usually on an emergency basis since it happens rapidly. Often the referral is for cataracts but compare this photo with the last one. You cannot see the brown iris clearly because the fluid in front of it is opaque, not the lens behind it.

Lipid flare in a dog with high blood cholesterol

There are certainly other lesions that can present as white in and around the eye. As I look out the window and see the snow piling up, I figure I have plenty of white to go around for a few more months. I even had to dig out Otto, our official greeter, so he wouldn’t get rolled by the plows! Good thing his eyes still look good….well, maybe!

Otto at the entrance to the AEC!

We see a lot of patients of all species that present with a complaint of cataracts in either or both eyes. I decided to post our owner information sheet that we give out if cataracts are present and cataract surgery is a consideration. A few basic points that I thought I would stress. 1) Nuclear sclerosis is an old aging change of the lens where the lenses appear grey but are not truly opaque and are often misconstrued for cataract. This is an increase in density of the lens that we see commonly in older patients. 2) Cataracts are not just an old aging change! We see many young dogs that present with cataract that are genetic in basis and occur at an early age (3-6 years). 3) Cataracts can present rapidly and may be associated with an inflammatory response or conversely, intraocular inflammation can cause cataract formation. 4) Age does not preclude anesthesia and successful cataract removal! It is an elective surgery, however, I have plenty of old dogs that were behaving like older dogs because of vision deficits that “are acting like puppies again” after having the cataracts removed. Hopefully the following information will help if you or your veterinarian see cataracts in your dog and are referred for possible cataract surgery.

Definition:

Cataracts are opacities in the lens of the eye. Although some people mistakenly think the cloudiness is on the surface (a “film on the eye”), it is actually a physical change within the lens which is deep inside your pets eyeball. A cataract may be very small and insignificant or can involve the entire lens and cause vision loss.

Insignificant incipient cataract

Why did your dog get cataracts?

Many cataracts are inherited and are found in breeds such as the Cocker Spaniel, Bichon Frise, Poodle, Siberian Husky, Miniature Schnauzer, Golden Retriever, Labrador Retriever and a number of terrier breeds. Other causes of cataracts include those secondary to Progressive Retinal Atrophy (PRA), diabetes mellitus, trauma, inflammation, geriatric change or puppy milk replacers. Many cataracts will worsen to the point of blindness but certain types, especially in the Retrievers, can remain small for the entire life of the pet. Cataracts are not limited to old dogs, especially the genetic based ones that can develop at an early age.

Lens-induced Uveitis:

A local inflammatory reaction inside the eye due to the development or progression of a cataract (lens-induced uveitis) can occur and is not uncommon. This can occur immediately upon the development of a cataract if this process is rapid (Bichon Frise commonly do this) or due to slow release of the liquefied lens proteins outside the lens capsule. This reaction can result in many complications such as retinal detachment, glaucoma, intraocular hemorrhage and scar formation.

Topical medications to control or prevent this inflammation are commonly utilized if inflammation is apparent or for prophylaxis of this inflammation if progression is suspected. These medications have no effect on cataract development but are used only to control or prevent this inflammatory reaction while you decide if surgical intervention is appropriate for your pet. This must be controlled prior to scheduling surgery if present. Unfortunately, some eyes become so inflamed that adhesions form, the cornea becomes compromised or other changes occur that can preclude successful surgery. Our goal at that point is to try and keep the eye comfortable.

Iris adhesion to lens from inflammation

How are cataracts treated?

Small cataracts do not warrant any intervention. We typically document the size and location and follow for progression if that possibility is suspected. Many cataracts are very small and are in a location that does not create worry and thus routine follow-up may be limited to your annual visits with your primary care veterinarian.

Treatment of significant cataracts is surgical removal of the lens with implantation of a man-made lens to return visual acuity back to normal. This is an elective procedure that is performed if you think improvement in vision will improve your pet’s quality of life. The procedure may be performed in one or both eyes depending on the specifics of each pet.

Prior to performing surgery, your pet may need to have special tests performed to evaluate the health of the retina (the “film in the camera”). An electroretinogram is like an EKG for the eye and evaluates retinal function. An ultrasound is utilized to detect any retinal detachment. These two tests are not painful, are usually performed without sedation and have virtually no risk associated with them. The tests take approximately 40 minutes to perform and we get the results immediately. If your pet does not pass these tests, removal of the cataracts may not be indicated and surgery would not be performed. These tests are not done on the day of surgery in this practice in case they fail. If the tests are successful, then surgery can be scheduled if your veterinarian confirms that anesthetic risk is low. Routine blood tests in addition to a physical exam will be advised for your veterinarian to assess this risk.

Normal ERG in a dog with cataracts

Cataract on the left, normal clear lens on the right

The surgery is performed under general anesthesia. The anesthetics are state-of-the-art medications that are used in human hospitals. Blood pressure, pulse rate, oxygen level, blood and respiration are monitored by a technician throughout the surgery. We make every effort to avoid complications but as with general anesthesia in any species, risks including death do exist.

Routine cataract surgery is performed using high-frequency ultrasound power to break the lens up into small pieces which are concurrently vacuumed out of the eye. This process is called phacoemulsification. This is performed through a small 3mm incision and is performed in over 95% of our patients. Phacoemulsification is the same technique performed for human cataract removal. Many people believe that cataract removal is done with a laser but that is not true for the primary cataract. After removal of the cataract, a new man-made lens is implanted to bring their visual acuity back to normal. We currently use foldable acrylic lenses that can be implanted through the same small incision. Although lens replacement is routine, it is sometimes inappropriate or impossible to implant a lens due to tears in the lens capsule or a breakdown of lens ligments which does not allow support of the new lens. Vision without a lens (aphakic vision) can be surprisingly good in dogs. Their view is now unobstructed by the cataract but out of focus due to the loss of the lens.

Phacoemulsification of the cataract

Cataract surgery is elective and requires a significant time commitment on your part. Eyedrops must be administered before and after surgery. These drops may be as high as 4 times a day for the first week but taper quickly over the next 2 weeks barring complication. The patient must wear a protective plastic collar for 2-3 weeks after surgery to prevent self-trauma. Postoperative checkups are usually performed the next day, one week after surgery, two weeks later and one month after that. At the time of the third postop exam, the protective collar is usually removed. Long term checkups are made about 4 months after surgery and then two times annually thereafter. Some dogs may need a drop a day continually as maintenance but many do not if inflammation and pressure are normalized. Expect to be medicating for at least 4-6 months after surgery. The success rate is over 90% but as with any surgery, there are risks.

Implanted intraocular lens after cataract surgery

What are the complications of cataract surgery?

There are five major complications of cataract removal: 1) Intraocular inflammation will occur due to the surgical trauma and thus most of the medications before, during and after surgery are geared towards controlling this reaction. Inflammation is the linchpin of most complications and is evaluated at every recheck. 2) Glaucoma is increased pressure inside the eye and can occur at any point after surgery. Mild to moderate elevations in pressure can be treated, but if the pressure goes up and stays up, irreversible vision loss can occur. This is the worst complication because it creates a painful blind eye that may require removal if uncontrolled. The general risk is 4%. 3) Retinal detachment is a painless blinding condition that carries a 2% complication rate. This can occur if a tear in the retina is created and the retina is pulled off or if inflammation pushes it off. Reattachment surgery is not common but is currently being performed by only a handful of specialists in the US. 4) Cataract regrowth can occur in 2 forms. Lens material may form globules that can contribute to inflammation. This is most common in young animals. The capsule that is left behind and houses the man-made lens commonly has or develops cataract as well. This regrowth is seen in basically all dogs but may not contribute greatly to vision impairment. Rarely is any surgical treatment required for either of these two entities. 5) Intraocular infection is a rare complication but is disastrous if it occurs and usually leads to loss of the eye.

I hope this information is helpful as you investigate cataracts and cataract surgery in the dog. A nice video clip is in the Helpful Resources section that has some images of the procedure, client testimonials and other tidbits that may be of value. As always, feel free to call the clinic and set up an appointment if you would like your friend evaluated.

Limbal Melanoma

The junction between the clear cornea and the white sclera is called the limbus and is a circular line that separates them. Melanoma can arise from here and is also considered benign. Growth, however, can occur and is more common in young animals than in old where it may remain static. If progression is suspected and your dog, less commonly cat, is affected, you have 3 basic choices. First is to remove the affected tissue and then graft in a donor piece of sclera to replace the wall of the eye that was resected. This is the most aggressive approach and carries the benefit of the surgeon being able to hold the tumor in their hand once removed and hopefully confirm complete excision. The negative is the invasiveness of the procedure and the inflammatory reaction that must be controlled both inside and outside the eye after surgery. The second and third is ablation of the tissue using cold (cryosurgery) or heat (laser). The mass is typically debulked or shaved off and the remaining pigmented tissue is destroyed by placement of the probe over the mass and treating the area. Although you are leaving tumor behind, this treatment is very successful, less invasive and reasonably well tolerated. The negative is that you are relying on your adjunct therapy to resolve the tumor rather than knowing you have completely removed it with resection. The area retains some pigment which has to be monitored for progression but usually remains a charcoal gray color. Both laser and cryo incur an inflammatory reaction to the eye which must be managed. Cryosurgery is my typical treatment of choice. The last option, especially in older dogs, is to measure, wait and watch as clinically they may not progress or progress quickly in which case there is little risk to leaving them there.

Limbal melanom in the dog

Limbal melanoma, post-op cryosurgery

Corneal Sequestrum

One of my favorite diseases in the cat is called a corneal sequestrum where the collagen of the cornea becomes discolored and turns a dark brown or black. It usually starts with a minor, poorly defined, tea-staining of the clear cornea, usually in the central region, and then progressively organizes and becomes more dense with well defined borders. In its beginning stages, it is not uncommon to see this associated with a corneal ulceration. What causes this pigmentation? Well, three basic entities are related to sequestrum formation. The first is breed which implies a genetic predisposition. We will see these develop more commonly in the Persion, Himalayan and Burmese cat although any cat can get one. Second is due to any low-grade, chronic irritation. The most common of these would be entropion, or rolling in of the lids. As the hair around the lid is directed onto the surface of the cornea, it is not uncommon to see ulceration and subsequent sequestrum formation that lines up with the offending hairs. The last is our friend the herpes virus, the most common cause of surface disease in the cat, which creates ulcerative disease of the cornea with deposition of pigment in the ulcer bed.

Treatment of corneal sequestra involves managing the primary problem (lid surgery if entropion, antivirals if herpetic, for example) and concurrently watching to see if the pigment dissipates or organizes. If an ulcerative problem is active and resolves, sometimes the tea color will dissipate as the ulcer heals. Sometimes the sequestrum will organize, develop sharp borders and the body will try to extrude or “kick it out” like a foreign body. This may take months but if the cat is comfortable, carries anesthetic risk for removal or has other issues to contend with, time may be on your side. If viral or genetic in basis, the ulcer may be difficult to heal, the eye remains painful and then this becomes a surgical problem.

Surgery involves shaving off the pigmented region of the cornea (keratectomy) and, depending on the depth of the pigment into the corneal tissue, subsequent grafting. Grafting of the cornea is performed if we have a structural weakness due to thinning of the cornea as a result of tissue removal that is greater than 50% of the true thickness. It may also potentially decrease the chance of recurrence which is not uncommon in this disease. The method of grafting depends on the size and depth of lesion and includes conjunctival grafts and corneoscleral transpositions. These methods are highly successful and result in a relatively clear cornea at the conclusion in the cat as we try to return to a comfortable and visual state.

Corneal sequestrum in a cat

Corneal sequestrum, post-op keratectomy

Pigmentary Keratopathy/Keratitis

Chronic, low-grade irritation comes in many flavors in the dog. Usually, a combination of exposure issues, hair abnormalities, dry eyes and genetic predisposition can result in slow and steady deposition of pigment in the clear cornea. Thererfore, breeds like the Pug, Pekinese and Shih Tzu are frequent fliers to our clinic because of this constellation of problems. Surface disease may resolve but the pigmentary change may continue. Treatment involves resolution of the primary problem (lid surgery? hair removal? tear replacement?) then monitoring for progression of the pigmentary component. If advancement is obvious, then medications to try to dissolve the pigment or slow its advancement are utilized. These drugs, primary tear stimulants, are the only true medications we have in our armamentarium to halt pigmentation and their response is unpredictable and often limited. Surgical removal of the pigment is only a temporary treatment since the pigment returns quickly. Thus, procedures to minimize the exposure component and improve protection of the cornea or tear distribution may be used together to try and halt vision loss in these cases.

Pigmentary keratopathy

Dense pigmentary keratopathy

As you can see, pigment in the eye comes in many forms so keep a look out and call if you notice anything that resembles these changes. Early diagnosis and intervention, as in most cases, may increase the possibility of a good outcome. Talk to you later!

Iris Cysts

Cysts inside the eye are a common and benign problem we see in dogs and, less commonly, cats on a regular basis. The ciliary body, which produces the fluid which bathes the front part of the eye, is lined by pigmented cells. In some instances, this tissue will bud off in the process of making fluid which causes a pigmented, fluid filled structure to peek out from behind the iris. As the processs continues, this cyst may release from behind the iris and float in the anterior chamber. As one may intuit, these cysts are typically round, see-through and mobile unless they become wedged between the clear cornea and the lens. This is a very common finding in the Goldern Retriever and Boston Terrier but can be seen in any breed. They are benign and warrant no treatment.

Iris Melanoma in the Dog

A melanoma in the iris or ciliary body of the dog is another common problem observed inside the eye. Although benign, meaning it will not spread outside of its location, it can be bad news for the eye as slow growth is expected. The presence of the mass can cause inflammation, cataract formation, retinal detachment and glaucoma. Usually, resection or laser destruction of the mass is not practical or successful unless quite small or easily approached. Therefore, removal of the eye to try and prevent it from becoming painful as well as confirming the benign nature of the mass by pathological evaluation is often advised. Eye removal sounds horrible but honestly dogs and cats do wonderfully with this surgery if warranted.

Iris melanoma

Iris Melanoma in the cat

Different than dogs, melanoma in the cat eye is determined as diffuse meaning it is not localized to a single location. The iris can become spotted with pigmentation change and does not form a visible lump like it does in the dog. Although considered malignant, meaning it can spread to distant locations, the progression to this state can take years. To confuse the matter, cats can get benign freckles on the iris that look identical and are probably an early version of the same process before the cells transform into cancer cells. In more advanced cases, the iris in the region of the pigmentation may take on a velvety look and pigmented cells may be seen floating in the fluid in front of the iris. Because of the slow development, we now take digital photos of the iris and follow for change. If these changes become concerning, eye removal may be advised if a systemic workup for metastasis is negative. Occasionally, irises that have progressed in pigmentation that are removed still receive a histopathological diagnosis of melanosis which is taken as a good sign that we may have gotten it out before it transformed to a malignancy. Below are two pictures of irises, one with melanoma and one with melanosis…..difficult to tell which is which, isn’t it?

I will talk about other diseases with a pigment component in the cornea in my next post….don’t forget to sunblock!

Iris melanoma

Iris melanosis