Pigmentary Keratitis in Dogs

Pigmentary keratitis is an eye condition commonly seen in certain dog breeds, characterized by the darkening or pigmentation of the cornea, the clear, dome-shaped surface that covers the front of the eye. This condition can lead to vision impairment and, in severe cases, blindness if left untreated. Understanding the causes, symptoms, and treatment options for pigmentary keratitis is essential for managing this condition and ensuring your dog’s eye health.

 

What Is Pigmentary Keratitis in Dogs?

Pigmentary keratitis is an eye condition in dogs characterized by the accumulation of dark brown or black pigment on the cornea, the clear front part of the eye. This condition typically occurs due to chronic irritation or inflammation of the cornea, leading to the deposit of melanin (the pigment responsible for color) in the affected areas.

Pigmentary keratitis is most commonly seen in brachycephalic (short-nosed) breeds like Pugs, Bulldogs, and Shih Tzus, as their prominent eyes are more prone to irritation from environmental factors, dry eye, or eyelid abnormalities. Over time, the pigment buildup can interfere with the dog's vision, potentially leading to partial or complete blindness if left untreated.

 

What Causes Pigmentary Keratitis in Dogs?

Pigmentary keratitis in dogs is primarily caused by chronic irritation or inflammation of the eye, leading to the deposition of melanin in the cornea. This condition often results from diseases of the eyelid, such as entropion (inwardly-rolled eyelid), ectropion (outwardly-rolled eyelid), abnormal eyelashes, or eyelid tumors, all of which can cause ongoing trauma to the eye’s surface.

Another common cause is keratoconjunctivitis sicca (KCS), or dry eye, where inadequate tear production leads to persistent inflammation. Dogs with abnormal blink reflexes are also at higher risk, as their inability to properly protect and lubricate their eyes contributes to the chronic irritation that triggers pigmentary keratitis. Additionally, some dogs may develop this condition after experiencing chronic or repeated corneal ulcers or previous corneal surgeries.

In some cases, an underlying cause for pigmentary keratitis cannot be identified, and the pigment may continue to accumulate even after the initial cause has been treated. This suggests a possible genetic component to the condition, particularly in breeds predisposed to eye issues.

 

Symptoms of Pigmentary Keratitis in Dogs 

The most noticeable symptom of pigmentary keratitis in dogs is the presence of a dark pigment deposit within the cornea. This pigment may be visible to the naked eye or may require closer examination to detect. The condition can affect one or both eyes and often appears as a brown or black spot on the cornea.

In addition to the visible pigment, other symptoms related to the underlying causes of pigmentary keratitis may include:

• Pain: Dogs may exhibit signs of discomfort, such as squinting or pawing at their eyes.
• Tearing with a Dry-Appearing Cornea: Despite excessive tearing, the cornea may appear dry, a common symptom in cases associated with dry eye (KCS).
• Swollen Blood Vessels in the Conjunctiva: The white part of the eye may show enlarged, swollen blood vessels due to chronic inflammation.
• Ropy Discharge: Thick, mucus-like discharge from the eye can be another sign of irritation or infection.
• Enlargement of the Eye: The affected eye may appear larger than normal, which can be a result of chronic inflammation or increased pressure within the eye.
• Redness of the Conjunctiva: The tissue around the eye may become red and inflamed, indicating ongoing irritation.

These symptoms, along with the visible pigment deposits, are key indicators of pigmentary keratitis and should prompt a visit to the veterinarian for a thorough examination and appropriate treatment.

 

When to contact your vet

You should contact your vet if you notice any signs of pigmentary keratitis in your dog, such as dark pigment deposits on the cornea, redness, or swelling around the eyes. Additionally, if your dog is showing symptoms of pain, excessive tearing, or a dry-appearing cornea, it’s important to seek veterinary care promptly.

Early intervention is crucial to prevent the condition from worsening and to address any underlying causes, such as eyelid abnormalities or dry eye, that may require specific treatment. If left untreated, pigmentary keratitis can lead to impaired vision or even blindness, so timely veterinary attention is essential for your dog’s eye health.

 

How Veterinarians Diagnose Pigmentary Keratitis in Dogs 

To accurately diagnose pigmentary keratitis, the veterinarian will conduct a thorough eye examination, often using a lighted ophthalmoscope to closely inspect the corneal surface. This tool helps bring the pigment into sharper focus and can also reveal any signs of trauma or damage to the eye. During the exam, the veterinarian will also check for underlying conditions that may be causing the inflammation. A Schirmer Tear Test may be performed to assess tear production and detect chronic dry eye (keratoconjunctivitis sicca). If ulcers are suspected, a fluorescein stain can be applied to the cornea to highlight any areas of damage. The vet will also examine the eyelids and eyelashes for malformations that could be contributing to the irritation.

In cases where glaucoma is a concern, the veterinarian will measure intraocular pressure to detect any increase, which could indicate the presence of the disease. If an infection is suspected, cultures may be taken and sent to a lab to identify the presence of fungi or bacteria. This comprehensive diagnostic approach ensures that any underlying causes of pigmentary keratitis are identified and appropriately treated.

 

Treatment of Pigmentary Keratitis in Dogs 

Treatment for pigmentary keratitis focuses on addressing the underlying cause of the corneal inflammation.

Surgery

Surgical options may include correcting eyelid malformations like entropion or ectropion and removing misdirected eyelashes. While surgery to remove corneal pigment has been attempted, it's generally avoided due to risks of scarring and infection.

Medications

Medications are used to treat infections and manage conditions like dry eye or glaucoma. Antifungal or antibiotic eye drops are prescribed for infections, while medications like tacrolimus or cyclosporine help reduce pigmentation and control dry eye. For chronic inflammation, corticosteroids are effective in reducing symptoms.

Overall, a combination of surgery and medication is often used to manage the condition and protect the dog’s vision.

 

Home Remedies for Dogs with Pigmentary Keratitis

While professional veterinary care is essential for managing pigmentary keratitis, there are some home remedies and supportive care measures you can use to help your dog:

• Artificial Tears: Regularly using artificial tear drops can help keep your dog’s eyes moist and reduce irritation. This is especially helpful if your dog has dry eye, a common contributing factor to pigmentary keratitis.

• Eye Protection: Consider using protective eyewear for your dog when they are outdoors or in environments with a lot of dust, wind, or sunlight. This can help reduce further irritation to the eyes and prevent worsening of the condition.

• Regular Eye Cleaning: Gently clean your dog’s eyes daily with a vet-recommended eye wash solution. This helps to remove debris, dust, and allergens that could exacerbate irritation and inflammation.

• Anti-Inflammatory Diet: Incorporate foods rich in Omega-3 fatty acids into your dog’s diet, such as fish oil supplements. These can help reduce overall inflammation, which may support eye health and slow the progression of pigmentation.

• Avoid Irritants: Keep your dog away from environments with high levels of airborne irritants, such as smoke, chemicals, or pollen, which can worsen eye irritation.

• Humidifiers: If your home is dry, using a humidifier can help keep the air moist, which may reduce eye dryness and irritation for your dog.

 

Preventing Pigmentary Keratitis in Dogs 

Preventing pigmentary keratitis in dogs involves a proactive approach to eye care and minimizing exposure to factors that cause chronic irritation. Regularly clean your dog’s eyes with a vet-recommended eye wash to remove debris, dust, and allergens that could contribute to irritation. For dogs prone to eye issues, consider using protective eyewear when outdoors to shield their eyes from wind, dust, and sunlight.

Managing underlying conditions like dry eye or entropion is crucial, as these can lead to chronic eye irritation that causes pigmentary keratitis. Regular veterinary check-ups are important for early detection and management of any eye conditions. Additionally, keeping the hair around your dog’s eyes trimmed can prevent it from irritating the cornea.

Maintaining a diet rich in anti-inflammatory nutrients, such as Omega-3 fatty acids, can also support eye health and reduce the risk of inflammation. By taking these steps, you can help protect your dog from developing pigmentary keratitis and ensure their eyes remain healthy.

 

Conclusion

Pigmentary keratitis in dogs is a serious eye condition that can lead to vision loss if not properly managed. By understanding the causes, recognizing the symptoms early, and working closely with your veterinarian, you can help protect your dog’s eye health and preserve their vision. Regular eye care and prompt treatment of underlying conditions are key to preventing and managing this condition effectively.