Conjunctivitis, which is often heard of in humans, is a disease that also occurs in dogs' eyes.

Conjunctivitis, which is often heard of in humans, is a disease that also occurs in dogs' eyes. There are three types of conjunctiva: the eyelid conjunctiva, which covers the inside of the eyelid; the ocular conjunctiva, which covers the front of the eye; and the conjunctiva of the blinker membrane, which covers the blinker membrane. Here, you will find a detailed explanation of this disease, along with methods of treatment.

What causes Conjunctivitis in dogs?

Conjunctivitis is a condition in which the white membrane called the conjunctiva, which covers the inside of the eyelid and the front of the eye to connect the eyelid to the eyeball, becomes inflamed. There are various causes of conjunctivitis, and when the cause is identified, a specific diagnostic name is given, such as “dry keratoconjunctivitis” or “allergic conjunctivitis”.

The following are the main possible causes:

1. Inflammation caused by foreign substances Foreign substances such as dirt, dust, shampoo, volatile organic compounds, and pollen can cause inflammation of the conjunctiva when they enter the eye. In the case of dogs with long hair, the hair around the eyes can get into the eyes and that can cause conjunctivitis. In addition, if the dog has an abnormal coat or eyelashes, such as eyelid entropion or upside-down eyelashes, the eyelashes and other hair will constantly enter the eye, which can irritate the conjunctiva and cause inflammation. If it is caused by a foreign object such as dust, dirt, or hair, it is more likely to occur in only one eye.

2. Bacterial and viral infections Since the conjunctiva is exposed to the outside air, it can become inflamed from infection by bacteria or viruses found in the air. One of the most common viruses is the distemper virus, and bacteria include staphylococci.

3. Complications of underlying diseases Conjunctivitis can be caused by some disease in the eye or body. In addition to eye diseases, keratitis, atopic dermatitis, sinusitis, etc. can also cause conjunctivitis.

4. Diseases of the immune system There is conjunctivitis, which occurs as a symptom of systemic allergies or atopy. It can cause redness around the eyes (whites of the eyes) and mucousy eye discharge.

5. Abnormalities in the tear fluid layer Conjunctivitis occurs when there is an abnormality in one of the two layers (mucin layer + water layer, oil layer) of the tear fluid. When the aqueous layer is reduced, the conjunctiva becomes bloodshot and sticky, while when the mucin or oil layer is abnormal, the conjunctiva is not so bloodshot and there is often a slight increase in mucousy eye discharge.

6. Parasite infection Conjunctivitis can be caused by an infection with a parasite called the oriental eye worm. The parasite is common in warm climates and is transmitted to the eyes of dogs by the nematode. In the case of parasitic infection, in addition to bloodshot conjunctiva, there may be a lot of mucousy eyes and tears, and rubbing of the eyes due to the irritating sensation of the worm.

What are the symptoms of Conjunctivitis in dogs?

To find out if the conjunctiva is inflamed, you need to push up on the upper eyelid or push down on the lower eyelid. This is because, unlike humans, dogs have very large black eyes (iris), so it is impossible to see abnormalities in the whites of their eyes just by looking at them from the front.

Symptoms of conjunctivitis that are easy for owners to notice may include:

• The whites of your dog's eyes are bloodshot

• The whites of your dog's eyes are bushy and saggy

• Your dog tries to rub his eyes with his paws

• Your dog rubs his eyes on the floor or wall

• Your dog blinks a lot

• Your dog seems to have difficulty in opening his eyes and squinting

• Tears increase

• Yellow eye discharge

Which dog breeds are the most exposed to Conjunctivitis in dogs?

Although all breeds of dogs are susceptible to conjunctivitis, short-headed breeds, which are especially prone to get foreign bodies due to their large size, and breeds prone to tear deficiency, are more likely to develop conjunctivitis because they are more susceptible to foreign bodies in their eyes and to bacterial and viral infections. In particular, cases of conjunctivitis are common in the following breeds:

• American Cocker Spaniel

• English Bulldog

• White Terrier

• Spaniel

• Shih Tzu

• Samoyed

• Pug

• Pekinese

• Lhasa Apso

How to diagnose Conjunctivitis in dogs?

Conjunctival hyperemia can be caused by a variety of conditions other than conjunctivitis, so it is important to have your veterinarian differentiate between conjunctival hyperemia being caused by conjunctivitis and other conditions. The veterinarian will diagnose conjunctivitis by the following steps:

1. Interrogation and visual examination After hearing the symptoms from the owner, the veterinarian will examine and check the condition of the dog's eyes and eyelids.

2. Measuring the amount of tears The veterinarian will measure the amount of tears to determine if the dog has keratoconjunctivitis sicca (KCS).

3. Intraocular pressure measurement A tonometer is used to measure the intraocular pressure to check for glaucoma. However, some veterinary clinics do not have tonometers, so if it is determined that an intraocular pressure test is necessary, you will be referred to a veterinary clinic that does have such equipment.

4. Slit-lamp examination Using an ophthalmic microscope, a narrow beam of light (slit lamp) is shone into the eye to observe the degree of bloodshot conjunctiva. It checks for blood vessels in the conjunctiva, blood vessels in the sclera, and damage to the cornea. If your veterinary clinic is not equipped with a slit lamp, ask for a referral to a veterinary clinic that can perform the test.

5. Cytology Under ophthalmic anesthesia, the conjunctiva is scraped with a special brush, and cells are collected to make a preparative specimen. The cells are examined under a microscope to determine the presence of bacterial infection and the nature of the cells.

How to treat Conjunctivitis in dogs?

Once a veterinarian has diagnosed conjunctivitis, different treatments will be given for different causes. If it turns out that conjunctivitis is caused by another systemic disease, the cause of the disease will be treated.

1. Cleaning to remove the foreign body To remove the foreign body that caused the inflammation, wash the eyes with a special liquid that cleanses the eyes. Depending on the object and location of the foreign body, it may be removed under local anesthesia or, in the case of less docile dogs, general anesthesia may be required to remove the foreign body.

2. Apply antibiotic or steroid eye drops If conjunctivitis is caused by a bacterial infection, antibiotic eye drops are applied to kill the bacteria and reduce the inflammation. If the conjunctivitis is caused by allergies, steroid eye drops will be applied. If it is found that conjunctivitis is caused by an eye or body disease, the original disease will be treated. In the case of systemic allergies, in addition to eye drops, steroids and anti-inflammatory medications are used for systemic treatment. For keratoconjunctivitis (KCS), which is caused by a decrease in tear volume or tear quality, treatment with artificial tears or immunosuppressive agents is used.

3. Take care not to get foreign objects in your eyes. When you shampoo your dog, be careful not to get detergent in his eyes. Routinely wash your dog's eyes after a walk with a cotton ball wetted with eye drops or a wet cotton ball that can be used to wipe the eyes (both for dogs and humans). For long-haired dogs, cut the hair around their faces short frequently to prevent hair from getting into their eyes

4. Determine the cause of the inflammation and avoid contact. If it is caused by allergies, find out what is causing the allergy, such as house dust or food, and avoid contact with it, or change the food to avoid feeding the allergen.

Diseases not to confound with Conjunctivitis in dogs The following diseases can be mistaken for conjunctivitis because their initial symptoms are similar to those of conjunctivitis.

• Glaucoma in dogs Glaucoma in dogs is a disease that can cause blindness due to increased pressure inside the eye, which presses on the optic nerve, one of the central nerves that cannot regenerate. In the early stages of primary glaucoma, the disease is asymptomatic, but as it progresses, the pupil remains dilated and the eye appears orange or green. As the disease worsens, the eye becomes larger and appears to be popping out of its socket. Unfortunately, it cannot be completely cured once it occurs.

• Uveitis in Dogs Uveitis in dogs is a disease that causes inflammation of the uvea of the eye, which consists of the iris, ciliary body, and choroid. Typical symptoms include a small pupil, redness, and pain in the whites of the eyes, stupefaction of the eyes, and increased eye discharge and tearing. Secondary glaucoma may also occur, causing visual impairment. At first glance, it is difficult to tell whether the cloudiness is in the anterior chamber or the lens.