Optic Neuritis In Dogs

Optic Neuritis (ON) is an autoimmune, demyelinating inflammatory condition of the optic nerve (which transmits visual stimuli from the eye to the brain). Optic neuritis represents a clinical syndrome more than a specific disease and often occurs alongside granulomatous meningoencephalomyelitis (GME) or, much less commonly with necrotizing leukoencephalitis (NLE).

In fact, “Optic Neuritis” is an umbrella term that comprises all diseases that cause signs in the optic nerve by primary demyelination. The symptoms usually manifest themselves as a partial (or total) loss of vision in one (or both) eyes or a sudden visual field defect. The main characteristic of ON is the recovery of all or part of the visual acuity gradually, however, brightness sensitivity and/or permanent residual deficits in color vision are common.

In dogs, inflammation of the optic nerves may be associated with inflammation in the brain or retinal inflammation or may involve the nerves only. There are several Causes of optic neuritis in the dog including viral infections, protozoal infections, fungal infections, tumors, Immune diseases, head trauma, and some forms of meningitis.

The optic nerve may be inflamed only in a portion of the nerve or along its entire length from the retina to the brain. When examining the retina - if the nerve beginning is inflamed, then that is visible. When the inflammation of the nerve is in the behind of the eye, the damage cannot be identified as the retina may appear normal.

• Blurred/diminished vision (usually the main symptom).
• Dilated Pupils
• Photopsia (flashing lights in one or both eyes).
• Swelling in optic nerve head.
• Blindness in rare cases.
• Pain with eye movement / Periocular pain
• Decrease in-depth perception.

• Treatment is directly dependent on the underlying cause of the inflammation. The cause of the optic neuritis must be identified in order for appropriate treatment to be instituted.
• When the optic neuritis is considered to be autoimmune in origin, or if meningitis is involved or idiopathic, corticosteroids such as prednisone and prednisolone are used to treat dogs to suppress the immune system.
• Anti-inflammatory medications, Antibiotics, and Pain Control Medications such as NSAIDs will be used to control infection and inflammation.

• When your dog is diagnosed with optic neuritis, ensure to follow precisely your vet’s medication instructions.
• Adhere to follow-up examinations schedule to monitor response to treatment and to identify any aggravation of the inflammation.
• Most of the dogs respond well to conservative treatment and get back their vision.

Preventative measures for optic neuritis are not available. Early diagnosis and appropriate medical intervention may prevent other neurologic signs from developing and ensure minimal optic nerve damage.

Beagle, Chihuahua, Bernese Mountain Dog, Dachshund, German Shorthaired Pointer, French bulldog, Irish Wolfhound, Papillon, Pekingese, Pug, Pembroke Welsh Corgi, Maltese, Nova Scotia Duck Tolling Retriever, Yorkshire Terrier, West Highland White Terrier

Risk Factors:

• Immune-mediated disorder of the Central Nervous System (CNS).
• Granulomatous Meningoencephalitis
• Viral Infections (Herpes, Distemper, CanineInfluenza or Hepatitis).
• Fungal Infections (Histoplasmosis, Blastomycosis, Valley Fever, Cryptococcosis).
• Parasitic Infections (Ehrlichiosis, Lyme Disease, Rocky Mountain Spotted Fever).
• Protozoal Infections (Neosporosis, Toxoplasmosis).
• Toxins
• Vitamin A deficiency
• Head Trauma
• Tumors
• Some forms of Meningitis
• Idiopathic - unknown causes

Types:

Acute Optic Neuritis:

• Monocular, Bilateral - occur in both eyes.
• Vision loss gradually develops over a period of time, peaking within 1-2 weeks.
• Vision loss, eye pain, and Worsened eye movement are the most common symptoms.
• An afferent pupillary defect always occurs when both eyes are uninvolved.
• Central Scotoma is the usual visual field defect seen in acute optic neuritis.

Chronic Optic Neuritis:

• Signs of optic neuritis can persist even after clinical recovery.
• These signs in dogs after recovery of optic neuritis may suggest an earlier, subclinical attack.
• Persistent visual loss, contrast sensitivity, deficits in color vision, light brightness, and stereo acuity.
• Despite the return of visual acuity after treatment, there will be some degree of Optic Atrophy.

Morbidity:

Optic Neuritis most commonly affects small to mid-sized dogs.

Canine optic neuritis is typically a manifestation of granulomatous meningoencephalitis or vice versa, it may progress to granulomatous meningoencephalitis.

ON is an immune-mediated demyelinating condition of the central nervous system (CNS).

The clinical manifestations are generally limited to afferent pupillary defects and acute vision loss. To ensure minimal permanent optic nerve damage, the diagnosis should be achieved quickly.

Diagnosis:

• Serum biochemistry profile and complete blood count.
• Tonometry, Slit Lamp and Fundoscopy.
• Inner Eye
• X-rays of the skull, chest, and abdomen or ultrasound to check metastasis.
• CT scan (bone involvement) and MRI (to check soft tissue damage).
• Fine needle aspiration or biopsy.

Mortality:

Although the mortality rate due to optic neuritis is less compared to other tumors, optic neuritis hugely impacts the quality of life of the dogs.

Prognosis:

The prognosis for dogs in advanced stages of optic neuritis is poor. Prognosis is often positive with early diagnosis and appropriate treatment. The outcome deteriorates in dogs that are not treated promptly or with severe signs.

Emergency - Immediate Veterinary Assistance Needed:

• If your dog blinks excessively or the eyes look painful and red continuously.
• Decreased depth perception.

Diet for eye health with anti-inflammatory foods diet:

The diet should be included foods containing vitamins A, C, omega 3s, zinc, carotenoids, beta-carotene, lycopene, and antioxidants.

• Omega-3 oily fishes such as salmon, tuna, cod, etc.
• Leafy greens such as spinach, kale, watercress, etc.
• Nonmeat/plant protein sources such as nuts, Lentils, Beans, Eggs, etc.
• Citrus fruits or juices, Sweet potatoes, tomatoes, pumpkin.
• Zinc foods such as Pork, tuna, and Oysters.
• Blueberries, Broccoli, cabbage, carrots, etc.

The ultimate prognosis for dogs with optic neuritis is eventually dependent upon the underlying cause of the disease. Dogs can have an improved quality of life for a period of time with proper treatment.