Veterinary ophthalmology: Animal cornea. How does a corneal ulcer occur in a cat and how dangerous is it?

One of the complications of keratitis is a corneal ulcer, in which the superficial epithelial layer is destroyed with further damage to deep structures. Due to the difficulties in differential diagnosis of erosions and ulcers, they are combined into the term “ulcerative keratitis.”

Causes of corneal ulcer in dogs

In dogs, the following precursor factors are more likely to predominate::

• Pathologies of the eyelids, which include entropions, dislocations, and injuries.
• Incorrectly or excessively growing long eyelashes, fur that touch the eyes.
• Dry cornea syndrome.
• Corneal ulcers in dogs can develop due to autoimmune diseases.
• Dystrophic lesion of the cornea.

Breeds such as bulldogs, Pekingese and others that have natural proptosis are more likely to develop corneal ulcers.

Corneal ulcer in dogs symptoms

There are 2 forms of the disease:

• Superficial. Characterized by damage to the epithelial layer and stroma.
• Deep. The process extends to the entire thickness of the stroma. Over time, discemet's membrane may become damaged, leading to perforation of the anterior membranes of the eye.

The acute stage (onset of the disease) is characterized by increased lacrimation and photophobia. The animal constantly tries to rub its eye with its paw, which aggravates the disease due to additional trauma and secondary infection. Redness of the conjunctiva appears, the eyelids spasm.

As the disease progresses, ulcers may form. If the process is left untreated, a perforated ulcer will develop, leading to panophthalmitis or prolapse. internal structures eyes.

In addition to perforation, other complications may develop. Over time, the cornea becomes overgrown with blood vessels, which leads to clouding, the appearance of pigmentation, and decreased visual acuity.

Causes of corneal ulcer in cats

In cats, the disease often develops due to eye diseases or internal organs, but other etiological factors also play a role:

• Herpesvirus is one of the common causes of ulceration.
• External irritants, which include smoke, ultraviolet radiation, chemical active substances, harmful fumes.
• Eye injuries.
• Disturbances in the innervation or blood supply of the cornea.

Corneal ulcers in cats may be caused by hereditary or anatomical reasons. Risk group breeds include exotics, Persian cats, Maine Coons.

Corneal ulcer in cats symptoms

Manifestations of ulcerative keratitis in cats are similar to those in dogs. More often they come to the fore purulent complications caused by infection, especially in pathologies caused by contact with the eye foreign body. In this case, the basement membrane of the epithelium is affected, the regenerative process is disrupted, as a result of which the corneal ulcer in cats takes longer to heal or does not heal at all.

There are general symptoms with redness, swelling, and lacrimation. Additionally, purulent discharge may appear, which indicates infection. Common cause Ulcerative keratitis in cats is a herpes virus, as evidenced by the appearance of symptoms after a respiratory illness.

Diagnostics

Diagnostic procedures are similar in cats and dogs. The veterinarian inspects all external elements ocular apparatus: corneas, conjunctiva, eyelids (including the third). To clarify the shape and depth of ulcers, they are used magnifying glasses. Next, the corneal reflexes and reaction to light are assessed.

A fluorescein test is mandatory, in which the damaged areas acquire a characteristic color. This method allows you to differential diagnosis with other red eye diseases (uveitis, glaucoma, conjunctivitis).

When found purulent discharge A bacterial study of the exudate is prescribed to identify the pathogen and determine sensitivity to antibiotics. Additionally, a Schirmer tear test and cytological analysis may be required.

Corneal ulcer in dogs treatment

A plastic collar is used to prevent further damage. First of all, drops and ointments containing antibiotics are prescribed, even if pathogenic microflora has not joined. This will prevent future infection.

Mild superficial forms usually do not require hospitalization and are treated with local drugs. To treat corneal ulcers in dogs, antibiotics and anti-inflammatory films are prescribed, and medications that improve tissue regeneration are prescribed. Surgery involves closing the defect with a conjunctival flap. After plastic surgery, improvement occurs within a week.

Treatment of corneal ulcer in cats

The general principles of treatment of the disease do not differ from those listed above. In view of frequent development herpesvirus keratitis requires careful sanitation chronic lesions infections. For this purpose, they are appointed antiviral drugs, mainly after relief of the symptoms of inflammation.

Cats often undergo tarsorrhaphy, in which the eye is “covered” by the third eyelid. This creates additional protection for the healing cornea.

To prevent pathology, it is necessary to monitor the behavior of the animal, give vaccinations in a timely manner, and if there is a suspicion of corneal damage, as soon as possible consult your veterinarian.

Forecast

Timely treatment allows you to preserve vision and prevent complications. During treatment, fluorescein tests are carried out, the results of which determine the degree of healing. Superficial forms epithelialize within 4-5 days. The healing time for deep defects varies from person to person (usually 3-4 weeks). The main factor influencing the recovery period is the treatment of the underlying disease that caused ulcerative keratitis. When eliminating it regenerative processes are accelerating.

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Ophthalmology for animals

Anatomy, hygiene, and other related factors often contribute to the development of eye problems throughout your pet's life. Diseases such as conjunctivitis can be treated quite quickly, but in some cases only a qualified veterinarian can help the animal. veterinary ophthalmologist

Keratitis in dogs: symptoms and treatment

Keratitis in dogs is a disease that is characterized by inflammation of the cornea of ​​the eye, usually has a pronounced symptomatic picture and must be diagnosed in order to prescribe the correct treatment.

Cataracts in dogs: symptoms and treatment

Cataracts in dogs are a common ophthalmological disease that worsens a dog’s vision and can also cause complete blindness. Cataracts in dogs are clouding of the lens, which prevents the passage of light into the eye.

The classification of eye diseases in cats and dogs is huge. And every disease “deserves” to be known not only by veterinarians, but also by pet owners. After all, knowing the reasons and characteristic Clinical signs You can recognize the disease in your mustache in time and seek qualified veterinary help.

Such fast reaction The owner will help save the cat or dog’s vision, and in some cases (when an infection is “connected” to the inflammation) and life. Yes, inflammatory processes (especially those caused by bacteria or viruses) extremely quickly “move” to the tissue surrounding the inflamed area. What's next to the eye? Brain. Therefore, often purulent conjunctivitis, keratitis and other sores “turn” first into panophthalmitis, and then through the ascending pathways (most often vessels) they “reach” the brain, causing meningitis, encephalitis and other diseases. Treating your pet becomes much more difficult.

Today we’ll talk about corneal ulcers. Why they arise, how to recognize them, what they threaten. And most importantly: what treatment does a dog with a corneal ulcer require?

Causes of corneal ulcers in dogs and cats

The most common cause of corneal ulcers in cats and dogs is a raging infection. Normally (in a healthy and strong animal), even a small scratch on the cornea heals quite quickly due to the accelerated division of special cells - keratocytes. However, if bacteria get into the wound and begin to release toxins during their life, the scratch will only begin to increase in size, turning into a wound. First, keratitis will develop, which will very quickly become a corneal ulcer in a dog or cat. But what can provoke such rapid destruction of the cornea?

Corneal injuries

It all starts with her. It is not necessary for a dog or cat to participate in a fight where he will receive a blow to the eye with an enemy’s claw or tooth. It is enough to stumble upon a dry twig or a hard blade of grass in the bushes. There are a lot of things that can damage an animal's eyes.

Prolonged conjunctivitis and keratitis in cats and dogs

When inflammation is prolonged and the animal does not receive proper treatment, corneal ulcers appear very quickly in cats. You shouldn’t leave such seemingly harmless diseases to chance, because they lead to serious consequences. Be sure to contact your veterinarian, even if you think you can handle everything on your own.

Infection

Bacteria and viruses multiply quickly, first causing conjunctivitis and keratitis, which then quickly “move to a higher level” - ulcers. It is not necessary that the cornea be injured. Many diseases of viral or bacterial etiology lead to inflammation of the cornea or conjunctiva. That is, keratoconjunctivitis is only a symptom of an underlying serious disease. And if the pet is not treated, then this inflammatory process becomes complicated, and the dog develops a corneal ulcer (photo below).

Predisposition to corneal ulcers

Short-faced and “bug-eyed” pets are more likely to suffer from corneal injuries than others. This happens because the eyelids do not close completely. Because of this, the eye is more likely to be injured. Who is at risk? Pekingese, bulldogs, Persians, pugs, boxers, Chihuahuas and others.

• Pathology of the eyelids. These include entropion of the eyelids (both congenital and acquired after blepharitis), trichiasis (growth of eyelashes towards the cornea), neoplasm on the eyelids.

Symptoms of corneal ulcers in dogs and cats

You can recognize the symptoms of a corneal ulcer in a dog yourself, but an examination by a veterinarian would be a good idea. He will confirm the diagnosis and prescribe treatment for the pet. This disease is also called ulcerative keratitis.

IN acute stage A lot of tears flow from my eyes. Photophobia again. Strabismus may also develop. The conjunctiva turns very red, a spasm of the eyelids is recorded.

If a dog with a corneal ulcer is left untreated for a long time, the vessels begin to grow into the cornea. However, there is a much greater risk that the eye will perforate and its contents will leak out.

If you look closely at the eye, you will notice ulcers of various sizes and diameters on the cornea. However, only a veterinarian can definitively confirm the diagnosis. To do this, he will drop a special solution onto the cornea (it will not cause any pain or the slightest discomfort to an already suffering pet), which has fluorescent properties. Then the rays of a special lamp will be directed at the eye, turning off the lights in the room. If there are ulcers, then their edges will be highlighted greenish (photo of a corneal ulcer in a dog detected using a fluorescent solution below)

Treatment of dogs and cats suffering from corneal ulcers

To prevent the pet from accidentally injuring its eye further, a special collar is put on the dog or cat. Antibacterial ointments are required to treat a dog with a corneal ulcer. Even if there are no bacteria in the wound now, it is better to prevent their appearance. It is enough to lay them once every 6 hours. Antibiotic drops must be used every 3-4 hours. Ointments last longer, but they need to be placed in the conjunctival sac (behind the lower eyelid). The most common drugs for treating cats with corneal ulcers contain erythromycin, gentamicin, terramycin, tobramycin and others.

IN small quantity One percent atropine is also used, gradually reducing the dose of the drug. The veterinarian will calculate everything. If the cause of a corneal ulcer in a dog is herpes, then antiviral drugs are prescribed.

To deal with a corrosive ulcer, veterinarian prescribes medications with anti-collagen properties.

However, sometimes the veterinarian decides to perform an operation to excise the damaged cornea and apply a piece of healthy conjunctiva. Over time, a healthy cornea will begin to recover; the main thing is to follow all the recommendations of the veterinarian and visit him regularly.

Prevention of corneal ulcers in dogs and cats

• Monitor your pet closely. Avoid walking through bushes or on mown and dried grass. And make sure there are no fights.
• Pay attention to any change in behavior or condition. If your cat or dog suddenly starts leaking tears from one eye (or maybe two at the same time), contact your veterinarian to have the animal examined. Even if the cause is conjunctivitis, it is better to get rid of it at an early stage than to later treat the dog for ulcerative keratitis.
• Vaccinate your animal according to age. Many infectious diseases cause inflammation of the cornea and conjunctiva, which can easily “turn” into an ulcer.

Still have questions? You can ask them to our site's resident veterinarian in the comment box below, who will respond to them as soon as possible.

Corneal defect and ocular vascular injection in a dog

By corneal ulcer we mean an unlimited process that spreads to the layers of the cornea, accompanied by loss of substance with prolonged purulent breakdown of cells. In most cases, this process is irreversible. In canine corneal ulcers, there is a complete absence of epithelium, exposing the underlying stroma. Corneal diseases occupy first place among eye diseases.

The causes of ulcerative keratitis can be either primary - trauma, exposure to chemical and physical agents, or secondary - due to a violation of the barrier function of the precorneal tear film, innervation of the cornea, systemic diseases internal organs. The clinical picture of different forms of ulcerative keratitis is characterized by polymorphism.

Causes of corneal ulcers – what causes eye damage?

The cornea consists of five layers:

1. pericorneal tear film;
2. epithelium and its basement membrane;
3. stroma;
4. Descemet's membrane;
5. endothelium.

Endothelial cells remove fluid from the stroma into aqueous humor. Intraocular pressure (IOP) promotes fluid flow into the cornea. When IOP increases, more fluid enters the cornea than is removed, leading to corneal edema. The epithelium also removes fluid. If the epithelium is damaged, fluid enters the cornea, causing corneal edema.

Causes of ulcers include abnormalities, foreign bodies, trauma, chemicals, inability to close the eyelids completely, and corneal diseases such as keratoconjunctivitis sicca.

Some types of hair can irritate the cornea and cause ulceration. If this cause is not removed, the cornea will not heal. You should be aware that not all animals with distichiasis should have abnormally growing hair removed. Most Cocker Spaniels have rows of these hairs, but they do not cause problems.

Staining the ulcerated area of ​​the eye

Trichiasis is the friction of the cornea by normally growing hair, which is caused by a violation of the structure of the eyelids. Examples of such situations leading to trichiasis are prominent nasal folds and entropion. Most cases of trichiasis can be successfully treated with surgery.

Other causes of persistent irritation:

• foreign bodies in the eyes can be deposited under the third eyelid and cause deep corneal ulcers;
• decrease in total tear production;
• turning of the eyelid into the eye, which causes regular injury to the epithelium by eyelashes and entry of bacteria into the wounds, which causes ulceration of the cornea;
• neurological disorders.
• chemical burn of the cornea when the dog comes into contact with household chemicals.

Violation of the integrity and nutrition of the cornea, necrosis of areas of the cornea, and lack of innervation ultimately lead to disruption of metabolic and microcirculatory processes in the cornea and reduce the resistance of the cornea to microorganisms. It is also worth noting that an ulcer can be caused by a complex of factors that affect the physiological barriers of the eye, which perform a protective antimicrobial function: meibomitis, blepharitis of various etiologies, exophthalmos, lagophthalmos.

Signs and diagnosis of the disease

The course of the ulcer is usually acute or chronic and depends on the origin and stage of development. On clinical examination, an ulcerative crater is observed on the cornea, around which diffuse opacification appears. Associated symptoms are lacrimation, pain, photophobia, and blepharospasm. The ulcer itself may be various shapes, outlines and depths.

Symptoms:

• pain and blepharospasm (often acute);
• photophobia;
• epiphora;
• corneal edema;
• the presence of a gaping corneal wound;
• pinching of partially fallen internal membranes and media in the wound;
• the presence of a wound canal in the projection of the corneal wound;
• the presence of a foreign body or air bubble in the anterior chamber;
• vascularization or pigmentation of the cornea (in chronic cases).

A purulent corneal ulcer is accompanied by severe pain, photophobia, blepharospasm, copious discharge from the conjunctival sac of mucopurulent exudate. Conjunctival and pericorneal injections and vascularization of the cornea are pronounced. A defect of various shapes is found on the cornea, the edges of which are uneven, necrotic, undermined, along the periphery of the corneal tissue are swollen, white-gray.

A creeping ulcer is characterized by the fact that diplococci or pneumococci that get into the cornea during injuries live and multiply in it. The disease begins acutely, severe pain, lacrimation, photophobia, hyperemia and swelling of the conjunctiva appear. A grayish-yellow infiltrate develops on the cornea, which quickly spreads and turns into an ulcer. The ulcer has undermined edges, the bottom is covered with a dirty yellowish coating. With a creeping ulcer, iritis often occurs, resulting in cloudy fluid or accumulation of exudate in the anterior chamber.

IN severe cases a perforated ulcer occurs. Outcome of corneal ulcers - scars varying intensity: leukoma, nubecula and macula.

An animal with corneal ulcers always experiences pain due to the development of epiphora, blepharospasm and conjunctival hyperemia. Diagnosis of corneal ulcers is very simple and is based on the inability of fluorescein to pass through the hydrophobic epithelium while being well absorbed by the hydrophilic stroma. After staining the ulcerated cornea with fluorescein and illuminating it through a cobalt blue filter, the ulcers are visible as green areas. Ulcers can extend throughout the thickness of the stroma to Descemet's membrane, forming a descemetocele. When stained with fluorescein, descemetocele appears as a green ring in the stroma with a clear center of Descemet's membrane, which does not absorb fluorescein.

Neuropathies ( seizures, paralysis facial nerve) led to long-term violation the process of blinking and the distribution of tears over the surface of the cornea, which inevitably led to disruption of nutrition, breathing and dryness of the cornea, which led to the formation of ulcers and their contamination with pathogenic microflora. Clinical symptoms were correlated depending on the severity of the pathological process in the cornea. Primary education ulcerative defect noted in the upper part of the cornea due to dysfunction upper eyelid. Were present brightly pronounced edema corneas, blepharospasm, photophobia, superficial vascularization of the cornea, serous-mucous and purulent discharge from the eye, perforated corneal ulcer with iris prolapse, lagophthalmos.

Methods for treating eye ulcers

Many body tissues repair themselves; corneal ulcers in dogs often heal without additional help. If only the epithelium is damaged, epithelial cells, surrounding the edges of the lesion, grow, closing the lesion. The entire cornea can recover in 4-7 days. With deep damage, another mechanism is noted:

• surface defects are filled with epithelial cells.
• deep defects are covered by epithelium, but further avasculation or vascular healing then occurs in the stroma.
• During avascular healing, neutrophils from the tear film or from the limbal conjunctival vessels migrate to the defect. Keratocytes in the lesion transform into fibroblasts and synthesize collagen and mucopolysaccharides, which fill the defect. Collagen fibers are arranged irregularly, which leads to the formation of an opaque scar. The density of the scar decreases over time, but the scar itself does not disappear.
• Vascular healing: vessels grow into the lesion from the limbus, allowing inflammatory cells and melanocytes to enter the lesion. Granulation tissue is formed and a denser scar is formed than with avascular healing. The vessels will eventually thin out and become difficult to see. However, they can be seen with a slit lamp.

But in most cases it is required veterinary care pet. Determine the cause and use it specific therapy to eliminate the root cause (for example, correcting entropion of the eyelids or removing foreign bodies). Combined treatment. If an ulcer occurs based on a non-contagious etiology, the cornea is disinfected with a 1% solution of hydrogen peroxide, a solution of ethacridine lactate (1:500), the bottom of the ulcer is extinguished daily with a 5% solution of iodine, followed by instillation in eyeball drops (“sofradex”, 10% sodium sulfacyl).

Initially, during aseptic processes, hydrocortisone is used in drops or ointments. In the future, with preventive and therapeutic purpose, especially in case of infection, drops and ointments of antibiotics (penicillin, tetracycline, chloramphenicol), sulfonamides (albucid), etc. are prescribed. If pus accumulates, the conjunctival sac is washed with solutions boric acid, ethacridine, lactate, furatsilin, furalgin, penicillin. For resorption of opacities with cessation acute inflammation use yellow mercury ointment, calomel with sugar in the finest powder, dionin in drops and ointments, in increasing concentrations (0.5-5%), tissue therapy, novocaine blockade.

Treatment regimen for corneal ulcers

Treatment regimen No. 2:

• antiherpetic eye ointments Virolex or Zovirax (acyclovir) is placed into the conjunctival sac 3 times a day for 14 days;
• antiviral, immunomodulating drops Aktipol, Poludan or Derinat 0.25% solution are used 1 drop 3 times a day for 14-21 days;
• antibacterial drops Floxal or Tobrex – 1 drop 3-4 times a day for 7-14 days;
• non-steroidal anti-inflammatory drugs Indocollir, Naklof or Diclof - 1 drop 2 times a day for 5 days;
• mydriatics and cycloplegics (atropine sulfate 1% solution or Cyclomed eye drops) should be used for the first 3 days, 1 drop 2 times a day;
• if dry keratoconjunctivitis was observed, then the hydrating tear substitute Vidisik was used, 1 drop 4-5 times a day;
• are also made subcutaneous injections Cycloferon 0.1 ml/kg of animal weight according to the scheme: days 1, 2, 4, 6, 8, 11, 14, 17, 20, 23;
• vitamin preparations are used systemically orally: Neuromultivit 0.5-1 tablet once a day for 20 days and Aevit 1 capsule once every 2-4 days for 5 doses.

Topical antibiotics should be used either prophylactically or based on culture results if an eye infection is present. For superficial and deep purulent keratitis and ulcers of the cornea, broad-spectrum antibiotics are used intramuscularly:

• kanamycin;
• monomycin;
• gentamicin.

The use of antibacterial ointment or solution is indicated local action every 6 hours, since the cornea is deprived of normal blood supply and is susceptible to infection. Best choice for the initial purpose are actions. Locally prescribed 1% eye ointments with erythromycin, dibiomycin, ditetracycline, oletethrin, eye films with neomycin or kanamycin. In case of severe keratitis, antibiotics are administered subconjunctivally (10-25 thousand units). Tobramycin, amikacin, and fluoroquinolones are also used to treat infected corneal ulcers, but they are not indicated for uncomplicated ulcers.

Atropine can be used as an iridocycloplegic.

Take measures to prevent progression of the disease (for example, use protease inhibitors or remove all free epithelial tissue, especially in the case of slow-healing ulcers). Local glucocorticoids are contraindicated in active corneal ulcers, because they increase collagenase activity 14 times and suppress epithelial and endothelial regeneration, fibroblast activity and infiltration inflammatory cells. Topical glucocorticoids can help resolve vascularity and scarring, but should only be used after the cornea has completed healing. Systemic glucocorticoids indicated if there is concomitant uveitis.

Purulent corneal ulcer in dogs

Surgery may be required to maintain corneal integration and create optimal conditions healing (eg, corneal repair with third eyelid flap, conjunctival flap, corneal transplant, corneal suturing). The third eyelid flap should only be used for superficial, non-infected ulcers. It minimizes contact of topical agents with the corneal surface and prevents visualization of any progression of the lesion. It is never used for deep ulcers or descemetoceles as it puts pressure on the eyeball and accelerates corneal rupture.

Deep or creeping corneal ulcers, as well as descemetoceles, are cases that require immediate surgical intervention and conjunctival or corneal transplantation. For a creeping corneal ulcer, diathermocoagulation of the edges of the ulcer is performed. Then use a 1% solution of atropine, a 0.25% solution of chloramphenicol, with sodium sulfapyridazine, and eye ointments.

If a large area of ​​the cornea is affected, a third eyelid flap or temporal tarsorrhaphy is used to close it. Of the two procedures, tarsorrhaphy is preferred because the medial portion of the cornea will remain visible for regular examination. Moreover, with partial tarsorrhaphy, direct application of medications is possible, and a third eyelid flap may impede access of medications to the cornea.

For persistent corneal ulcers, cribriform keratotomy is performed. The first step is to remove all exfoliated epithelium cotton swab(the owner should be warned that the ulcer will be much larger than it appears upon superficial examination). Then a lattice is created using a needle. The keratotomy begins with a healthy cornea, then moves to an ulcer and ends again on a normal cornea. To avoid perforation of the cornea, the author recommends holding the needle almost parallel to the surface of the cornea, placing your hand on the animal's head. At the same time, the keratotomy must be of appropriate depth, so the latticework must be visible after surgery. After surgery, contact lenses are worn to increase adhesion between the epithelium and stroma. Debridement and keratotomy are very painful procedures, so atropine is used to relieve pain local application every 12-24 hours for 2-3 days and oral aspirin for several days. Topical antibiotics are also indicated, as with any ulcers.

Washing the eyes when peptic ulcer

In calm animals, keratotomy can also be performed in the emergency room. To calm nervous animals it is necessary sedatives. After sedation and contact lens placement, temporal tarsorrhaphy is performed to increase contact lens retention time. If it is not possible to purchase contact lenses, then a flap is created from the third eyelid. According to the author, non-healing ulcers are a direct indication for creating a third eyelid flap. The owner should be warned about the length of the recovery period, as well as possible relapses.

The animal is put on a protective “Elizabethan collar” if it tries to rub its eye. After scarring of a corneal ulcer, it is necessary to use absorbable drugs (fibs, aloe, etc. - intramuscularly), and locally - “oftan-katachrome” drops, vitamins and their analogues. Good effect provides local laser therapy.

Elizabethan collar on a dog to prevent secondary injuries

Along with the generally accepted drug treatment animals can receive physiotherapeutic treatment with a low-frequency pulsating magnetic field of 10 mT with a frequency of 50 Hz using the Magniter AMT-02 device using a stable method, with a gap from the surface of the eye of 1-2 cm. The course of treatment with low-frequency magnetic therapy is 10 minutes daily. Depending on the observed objective improvement, sick dogs receive a course of 1 to 10 sessions. At the end of treatment, a decrease or complete disappearance of photophobia and blepharospasm is observed. Objective symptoms were expressed in a decrease in edema of both the endothelium and epithelium, the roughness of the cornea was smoothed out. Magnetic therapy can improve the restoration of the cornea in case of peptic ulcers and injuries.

A dog’s clean, clear eyes are one of the most objective signs that indicate the animal’s excellent health. If a dog is moping for one reason or another, it will never have clear eyes. And it's good if we're talking about about a relatively “harmless” thing. Much worse if developed corneal ulcer in a dog: this pathology may well lead to complete loss of vision, or even the entire eyeball.

This ulcer is a defect in the uppermost, epithelial layer of the cornea.. In principle, this pathology can be considered a kind of analogue of a scratch on the skin, although the consequences are, without a doubt, very serious. And further. There are a lot of things in the cornea nerve endings, and therefore any ulcerative lesion leads to the development of a strong pain reaction, which prevents your pet from eating and sleeping normally, which quickly leads to physical and nervous exhaustion. Since as a result of this the protective epithelial layer is degraded, the eye becomes much more susceptible to various bacterial infections. This is very bad because common consequence bacterial infection eye – complete loss of vision.

Why does this happen? To answer this question, you need to know about the structure of the cornea in principle. Its first layer is the same epithelium that plays a protective role. Just below is the stroma, which is the basis of the entire cornea. The final layer is Dessemet membrane. All these areas are quite thin, and therefore any injury, ulcer or other pathology is potentially very dangerous.

About dangerous and “non-dangerous” types of corneal ulcers

You need to understand that the cornea is not a monolithic armor. It is regularly damaged by grains of sand caught in the conjunctival cavity by eyelashes, etc. foreign objects. In addition, the dog himself can injure his cornea by scratching his eyes too zealously with his paws. All this, to one degree or another, is fraught with the development of ulcerative lesions, but not all of them represent real danger for the dog's health.

The fact is that a simple ulcer heals within a week maximum. A feature of this type of pathology is the absence of a pronounced pain reaction. Unfortunately, in many cases, such ulcers gradually progress, causing the animal to subsequently lose vision. Alas, many owners do not understand the seriousness of the phenomenon.

Remember! Corneal lesions cannot be seen with the naked eye, so people do not take their pet to the vet immediately.

If the veterinarian does not find anything serious during the examination, the dog will (most likely) be prescribed some drops with a disinfecting effect, and the treatment will be completed. It should be noted that sometimes such ulcers develop into chronic form and can heal within six months. These are the types that are known as “Boxer ulcers,” by the way. Thus, our advice is simple - if you have the slightest suspicion that something is wrong with your pet’s eyes, you need to immediately contact your veterinarian.

Read also: Pityriasis versicolor in dogs: diagnosis, treatment, prevention

Predisposing factors

The development of a corneal ulcer is usually begins after damage to the epithelial layer of the organ. But why this can happen is another question. In particular, one of the most common reasons is mechanical injuries corneas, especially often obtained by service and hunting dogs. Grass stubble, sand, earth, etc. get into their eyes foreign objects. Their danger lies not only in mechanical injury to the cornea - a large amount of pathogenic and conditionally pathogenic microflora is introduced into the eye, which almost inevitably leads to the development of inflammation.

There are other reasons. In particular, if the dog lives in your home, he may gain “unauthorized” access to household chemicals and other irritants. The consequences are very serious. In particular, this is how a perforated corneal ulcer can appear, in which all layers of the organ melt, and sometimes the eye sclera is immediately damaged.

Cases of entropion of the eyelids are extremely dangerous. In these cases, the eyelashes constantly scratch and wound the surface of the cornea, and the microflora that gets into the eye quickly contaminates the resulting wounds. Because of this pathological process progresses very quickly, an ulcer soon develops. And in this case, by the way, there is no doubt about its presence. Eyelashes injure the front surface of the eye so much that even the most inexperienced breeder can see something wrong.

A corneal ulcer can result from any infection. accompanied by purulent conjunctivitis. The fact is that pus has a powerful proteolytic effect, that is, it is capable of corroding protein structures. Simply put, purulent exudate is a powerful solvent. Moreover, the thinner it is, the better this property is expressed. So if you see that your dog has something yellowish-green running from his eyes, go to the vet immediately! Even a small grain of sand or grass stubble that leads to suppuration can be the cause total loss your pet's vision!

Clinical picture and diagnosis

At first, clinical signs are either almost invisible, or (more often) they may not exist at all. But after a few days everything changes. Since the tissues of the cornea contain a mass of nerve endings, the sick animal develops a strong pain reaction. As a result, the dog begins to constantly rub his eyes with his paws, often squeals and whines, and cannot sleep, eat or even drink normally.

Soon everything becomes even worse: the dog begins to constantly squint, looks sideways at everyone, and crusts of exudate quickly accumulate in the corners of the eyes.

Due to severe pain, the animal tries not to blink again, and therefore constantly sits with its eyes tightly closed.

In addition, the pet develops severe photophobia: he avoids looking at light sources, since the latter causes him pain.

How can you understand that a dog has developed a corneal ulcer, and not simple conjunctivitis, for example? It is not so easy. We have already said that each of the corneal layers is very thin, and therefore it is impossible to determine “by eye” that any of them has an ulcerative lesion. This is why veterinarians use fluorescent dyes. Once applied to the cornea, such a dye is evenly distributed throughout the tissues, including the ulcer (at the same time clearly delineating its boundaries).

Read also: Do dogs have headaches? How not to miss dangerous symptoms

When a special UV light is shined on the pre-treated cornea, the dye begins to shimmer brightly. If there are any defects on the fabrics, in such conditions they are easy to notice. The same technique, by the way, is used in human ophthalmology. So, for example, you can check how severely the eye is damaged after getting into it metal shavings, glass shards, etc.

In some cases, especially when it is suspected infectious origin ulcers, a tissue sample may be taken for cytology and microscopic examination, as well as for sowing samples on nutrient media. Their results will help the specialist find out which microorganism is responsible for the dog’s condition, and what kind of drugs should be used to suppress it.

Therapeutic techniques

Note that the treatment of corneal ulcers in dogs includes many techniques that have long been used in practice, so when timely application you will almost certainly be able to save your dog’s vision. Do not worry: Today, most cases of ulcers are treated without surgery, To surgical intervention specialists prefer to resort only to the most advanced cases. Unfortunately, this only applies to those situations where the owners brought their dog to the clinic on time. If your pet has liters of pus leaking from his eye, and he cannot open his eyelids at all due to severe pain, surgery is no longer possible. How is it done?

Most often they resort to keratotomy(simple cutting of the cornea to straighten it) and keratectomy (that is, complete removal of dead tissue. As a rule, keratotomy shows good results (very good - up to 95% of success). Its advantage lies not only in simplicity. Most dogs only need fixation and local anesthesia. No anesthesia or powerful painkillers are needed. But here everything, of course, depends on individual characteristics specific animal.

Unfortunately, kerotectomy is a more complex and traumatic method. The dog must not be allowed to have even the slightest opportunity to move during the procedure, and therefore general anesthesia is used. In this case, either a special diamond “cutter” or a laser is used for the operation, which actually evaporates the dead and ulcerated parts of the cornea. The technique is much more expensive, but has an almost 100% success rate. Of course, only a specialist with extensive experience and experience should perform the operation, since in otherwise The patient's vision may be permanently damaged. The advantages of this technique include fast recovery functions of the cornea. In fact, immediately after recovering from anesthesia, the animal can already see relatively normally.

Auxiliary techniques

Regardless of the procedure your veterinarian chooses to eliminate the ulcer, be sure to prescribe auxiliary treatment. It is necessary to protect against secondary infection, eliminate pain and other unpleasant sensations.

An extremely important task The veterinarian and the animal owner himself should avoid licking and scratching the treated eye, since otherwise all efforts to eliminate the pathology may be in vain!

So, what drugs are prescribed for all this? First, a dog with a corneal ulcer needs to regularly moisturize the surface of the sclera. Secondly, it is necessary to prevent the development of pathogenic and conditionally pathogenic microflora. To accomplish all this, the animal must regularly instill products with an antiseptic and anesthetic effect into the eyes. Anesthetics are very important (sometimes lidocaine is used), since without them the animal cannot drink and eat normally, suffering from severe pain in the eye.

Ulcerative lesions of the cornea are called ulcerative keratitis - this is a serious eye disease that can lead to serious consequences, including complete blindness of the pet. This pathology is detected in both humans and dogs. But it doesn’t matter who the patient is, the main thing is that the patient receives timely medical care. What are the dangers of corneal ulcers in dogs and how is this disease treated?

The corneal layer is the anterior part of the membrane of the organ of vision, which includes several layers:

• upper – epithelial, is the protective membrane of the organ of vision;
• then follows the stroma - the basis of the entire cornea;
• Dessemet's membrane (Dessemet's membrane) – posterior border wall;
• the posterior epithelial layer is the corneal endothelium; it maintains slight dehydration of the eyeball.

IN in good condition the cornea has a smooth, transparent surface, without any roughness, and there are no vessels in its layers circulatory system. And since it contains great amount nerve roots, this area is characterized by increased sensitivity.

Ulcerative lesions of the cornea affect its uppermost epithelial layer. If we draw an analogy with skin damage, then an ulcer is a scratch, but not of the skin, but of the corneal layer, and this pathology is considered more dangerous.

The condition of a sick animal suffering from an ulcer is aggravated by the fact that due to the abundance of nerve endings in the cornea, this form Keratitis is accompanied by unbearable pain. The pain knocks the pet out of its usual rut, does not allow it to eat normally, rest, and causes insomnia. This condition quickly leads to nervous and physical exhaustion dogs.

Against the background of damage, the epithelial layer of the eye degrades quite quickly, and the organ loses reliable protection from various kinds infectious pathogens. Ulcerative keratitis is serious pathology, a complication of which is often bacterial infection of the eyes and subsequent blindness.

Types of erosion and causes of their occurrence

Similar peptic ulcer difficult to treat and recurs very often. Most often, infectious ulcers are caused by staphylococcus, streptococcus, Pseudomonas aeruginosa, herpes virus, coronaviruses, and Koch's bacillus. In addition, chlamydial infection can cause ulcerative keratitis in pets.

In case of non-infectious keratitis, the following conditions can be factors that provoke the appearance of ulcerations on the corneal layer:

• breed predisposition - most often eye pathologies develop in dogs with bulging eyes(brachycephalic) – Pekingese, Japanese Chins, Shih Tzu, Boston Terriers, French bulldogs, Great Danes, Labradors, etc.;
• foreign body entering the cornea and third eyelid;
• change in the position of the eyelids (entropions);
• dry eye syndrome;
• burn of the mucous membrane of the eye - chemical, thermal, ultraviolet, etc.;
• impaired growth of eyelashes (districhiasis, cilia) which begin to scratch and rub the surface of the cornea;
• limbal corneal insufficiency;
• decreased local immunity.

Experts also distinguish between superficial and deep ulcerative keratitis:

• superficial pathology - the lesion affects the epithelial layer and stroma of the cornea;
• deep pathology - ulcerations extend to all layers of the stroma. As the disease progresses, the pathological process penetrates into the thickness of the cornea, affecting the discemet membrane, which threatens perforation of the anterior membrane of the eyeball;
• Descemetocele is a condition in which complete perforation of the corneal layers occurs, when a through lesion appears and reaches the Descemet layer.

Chronic erosion of the cornea, in which damage long time don't heal. The pathology is called endolent erosion or boxer's ulcer. The risk group for this pathology includes representatives of the following breeds: boxer, dachshund, spaniel, spitz, etc. Most often, the disease is diagnosed in animals older than 5 years.

The peculiarity of keratitis in this case is that the damage may not heal for weeks, and no visible reasons there is no reason for this, and the medications used do not have a positive effect.

The cause of the disease lies deep - there is a failure in the contact of epithelial cells with the cells of the basement membrane, so normally recovering epithelial tissues cannot attach to the membrane, and they desquamate. Naturally, in such conditions there is simply nothing to cover the damaged area with.

Quite often, ulcerative keratitis does not have pronounced signs, and the dog owner does not notice that his pet is sick. But over time, the disease progresses, the dog begins to feel severe pain and discomfort. At the first symptoms of the disease, the dog should be shown to a veterinarian.

Symptoms of Corneal Ulcers in Dogs

When should a dog owner be concerned about the condition of his pet? In the acute stage, corneal erosion is accompanied by increased secretion tear fluid and photophobia.

The pet makes constant attempts to rub its eyes with its paws, which further aggravates the condition visual organ– in this situation, injury to the damaged organ and secondary infection of existing wounds are possible. The conjunctiva turns red and spasms of the eyelids occur.

Gradually, existing ulcers become more noticeable; if the pathology is not treated, a perforated ulcer may occur. A complication of this condition is panophthalmitis - an acute purulent inflammatory process that affects all tissues and membranes of the visual organ or loss internal parts eyes.

Diagnosis of the development of corneal ulcers in dogs

In case of eye diseases in dogs, the owner is recommended to contact a veterinary clinic that provides specialized services. In this case, consultation with a veterinary ophthalmologist is advisable. In addition, similar medical institutions have all the necessary instruments and apparatus that allow the most accurate diagnosis of pathology.

But if this is not possible, it is still worth taking your pet to the nearest veterinary center. First of all, the doctor examines the patient, identifying violations:

• external examination allows you to assess whether both organs of vision are symmetrically located and deep;
• a test for reflex abilities is carried out;
• the specialist checks whether pain symptoms are present.

Using an ophthalmoscope and a slit lamp, the ophthalmologist examines the eyelid, cornea and anterior chamber of the organ. This is possible if there is no severe clouding of the cornea.

The doctor has several specific techniques in his arsenal that allow him to conduct a number of tests:

1. Schirmer test - makes it possible to study the process of tear secretion in order to identify dry eye syndrome. To carry out the test, a strip of filter paper is folded at the edge and placed behind the lower eyelid. Within 5 minutes it is saturated with tear fluid if the eye is healthy. In case of pathology, the paper remains completely dry.
2. The Seidel test with fluorescein is a technique in ophthalmology that allows you to detect damage penetrating the cornea; it is also used as a additional method studies of the activity of the lacrimal gland. The test is carried out as follows: a specialist applies a local anesthetic to the corneal surface and instills eye drops 2-3 times. Afterwards a fluorescent solution is applied. The doctor then applies light pressure on the eye with a cotton swab, assessing leakage from the damaged area in the light ultraviolet lamp. If a dark stripe washes out from the ulceration down onto the green background, then the test is considered positive and the organ is perforated. In this case, emergency microsurgical sealing of the wound is required.

If during diagnosis an eroded area is detected, the specialist examines the edges of the eyelids and assesses the condition of the conjunctival sac. During the process, it is possible to detect provoking factors: ectopic eyelashes, aggressively growing hard distichiasis eyelashes, neoplasms, foreign components.

Treatment of corneal ulcer

First of all, having assessed the condition of the four-legged patient’s cornea, the veterinarian decides whether it is possible to solve the problem with the help of conservative therapy or more serious surgical intervention is required.

Traditionally, treatment includes the use of medications:

1. Antibiotics. If ulcerative keratitis is caused by an infectious pathogen, then local antibacterial drugs are prescribed. Ointments or medicated liquids are applied to the surface of the eye. Medicines are selected individually, depending on infectious agent, severity of damage, breed and age of the animal. Most often, the specialist recommends the use of Tetracycline, Erythromycin ophthalmic ointment, provided that the pathogen is sensitive to such antibiotics. When infected with Pseudomonas aeruginosa, a solution of Polymyxin M sulfate is instilled into the dog's eyes, and Neomycin is injected under the conjunctiva.
2. Drugs that dilate the pupil. For these purposes, ophthalmology successfully uses medicine Atropine in the form of an ointment or solution. The drug is used every 8-24 hours, gradually reducing the dosage.
3. Antiviral drugs. Their use is required for the herpetic form of ulcerative keratitis in dogs. A solution of Trifluridine or Idoxuridine is instilled into the affected eye at intervals of 4-6 hours until clinical improvement is achieved. Then the dosage is gradually reduced over 1-2 weeks.
4. Preparations with anticollagenolytic effect. Acetylcysteine ​​is most often used to treat corrosive ulcerations. 20% of the medicine is diluted in artificial tear fluid until the concentration is 5-10%. The resulting product is instilled into the eye at intervals of 2-4 hours. In addition, this medicine can be mixed with antibacterial drugs, for example, Gentamicin is added to Acetylcysteine ​​and the drugs are diluted with artificial tears.
5. Nonsteroidal anti-inflammatory drugs (NSAIDs). Drugs in this group have a pronounced anti-inflammatory and analgesic effect. To treat animals from this group, acetylsalicylic acid (Aspirin) is often used; for dogs, a single dose is 10-15 mg, given at intervals of 12 hours.

If the veterinarian prescribes several drugs, then they should be used with a mandatory break, which should be at least 5 minutes.

If your pet suffers from chronic corneal erosion, then traditional therapeutic techniques will not help, since they do not ensure the attachment of epithelial cells.

For treatment chronic illness use following methods therapy:

1. Removal of loose epithelial tissue using a cotton swab. After the procedure, the damaged surface is exposed, which most often turns out to be more extensive. Afterwards it is applied to the cornea medications, having a pronounced antimicrobial effect. For the procedure use local anesthetics as eye drops. The measure is low in effectiveness, and the patient requires several treatments at some intervals. The corneal tissue heals slowly, and rough scar tissue often forms in its place.
2. Keratomy is a method in which a number of different incisions are applied to the surface of the corneal layer, having a recess into the surface of the stroma. Used during the event insulin needle. If the dog calmly responds to doctors and intervention, local anesthesia is applied. But more often, animals need sedation, which is combined with covering the organ of vision with an apron of the third eyelid, which increases the rate of healing. The effectiveness of surgical intervention is on average 70%.
3. Treatment of the eroded area with a diamond bur. This is a specific device suitable for scarification of the cornea. With its use, the ophthalmologist removes unattached areas of the epithelium, creating a surface suitable for better engraftment of renewed tissues. Among the advantages of this procedure, we can note the possibility of carrying it out without the use of general anesthesia; only the administration of a drug with a local anesthetic effect is sufficient. In some cases, the procedure must be repeated after 1-2 weeks, there is a risk of formation rough scars during healing of injuries.
4. Keratectomy is an operation during which the upper corneal layer is removed along with the affected thin basal membrane layer and part of the stroma. Healing of erosion occurs due to the complete restoration of the surface part, and not just the epithelial layer.

If the disease in any form is not treated, you can expect serious complications, the pet may go blind or lose its eyes completely. To avoid such severe conditions, you should be more attentive to your pet’s health, especially if there is a predisposition to eye diseases. Even with minor pathologies, the dog needs to be examined by a veterinarian.