Dog Care: Understanding Optic Neuritis

Optic neuritis is a serious eye condition that causes the optic nerve to become inflamed. This is the nerve that's responsible for transferring images received by the retina at the back of the eye to the brain for processing. Optic neuritis causes impaired vision and damage to your dog's sight can be permanent if it's left untreated. Here's what you need to know about optic neuritis in dogs:

Causes And Symptoms

Causes of optic neuritis include a tumour growth on the optic nerve, a fungal infection and toxoplasmosis, which is a parasitic infection that's spread through infected faeces, digging in infected soil or consuming undercooked meat that's infected with the parasite. Optic neuritis can also come about as a result of lead poisoning, but this is now a rare occurrence in dogs.

Symptoms of optic neuritis include bleeding at the back of the eye, dilated pupils and vision loss, which can be complete or partial. Vision loss can present as clumsiness, confusion and withdrawal from play. Your dog may also become easily irritated or frightened in new situations or environments. Your dog's pupils may also have a delayed response to exposure to bright light.

Diagnosis And Treatment

Your vet will examine your dog's eyes with a slit lamp. This is a type of microscope that enables the back of the eye to be assessed. They will also use diagnostic imaging, such as an MRI or CT scan, to determine if the optic nerve is swollen, if a growth is present or if there's bleeding. Urine and blood tests can be used to check for the presence of infection, which can be indicated by a raised white blood cell count and the presence of protein in your dog's urine.

Treatment for optic neuritis depends on the identified cause, but your dog will be prescribed corticosteroids to bring the inflammation down and encourage healing. If an infection has caused optic neuritis, your dog will require antibiotics or antifungals, which are administered orally. A tumour can be surgically removed, but this isn't always recommended due to the proximity of the optic nerve to the brain. Your vet will discuss the advantages and risks of this surgery with you. Toxoplasmosis is treated with drugs that prevent the parasites form multiplying, and it can take some time for the existing parasites to die.

If your dog has any of the symptoms associated with optic neuritis, or if you have concerns about the health of their eyes, book an appointment with your vet as soon as possible.