Time is of the essence for saving your dog’s vision. If you notice your dog has one or both eyes bulging, or has an oddly colored eye or a strange discharge from the eye-get your dog to your veterinarian as soon as possible. Thanks for reading and if you have any questions about anisocoria or are concerned your dog has uneven pupils, please contact your veterinarian.There are a number of reasons for a dog’s eye or eyes to begin bulging unnaturally. If the anisocoria is due to an underlying medical condition, treatment will be focused on that condition.

In some cases, no treatment may be necessary if the condition is not causing any problems for the dog. While usually harmless, it is important to have any changes in pupil size evaluated by a veterinarian as they may be indicative of an underlying medical condition that needs to be treated. In conclusion, anisocoria in dogs is a condition in which the pupils of one or both eyes are different sizes. If anterior uveitis is the cause, the dog will need to be treated with anti-inflammatory medications. If the anisocoria is due to an underlying medical condition, treatment will be focused on that condition.įor example, if glaucoma is the cause of anisocoria, the dog will need to be treated with medications to lower the intraocular pressure. The treatment for anisocoria will depend on the underlying cause. What are the treatment options for anisocoria in dogs?

When utilizing these medications to determine the cause of anisocoria, it's essential to keep usage periods apart by 24 hours since together, they might influence each other's activity. Examples include phenylephrine, hydroxyamphetamine, and pilocarpine. Your veterinarian can also use single-dose ocular medications to better determine the cause of anisocoria which is referred to as pharmacological testing. The evaluation of the degree of anisocoria in dim and bright light settings allows for the diagnosis of an abnormal pupil, narrowing down the possibilities. The vet will perform a thorough ocular and neurological examination and may also recommend other tests, such as blood work or imaging, to rule out any underlying medical conditions. Oculomotor nerve lesion: This is a condition in which the oculomotor nerve (CN III), which controls the movement of the eyeball and the muscles that control pupil size, is damaged.Īnisocoria is usually diagnosed during a detailed physical examination by a veterinarian.It is usually an age-related issue and occurs commonly in senior dogs. Iris atrophy: This is a condition in which the iris (the coloured part of the eye) deteriorates.It can damage the optic nerve and lead to blindness if not treated promptly. Glaucoma: This is a condition in which the pressure inside the eye is too high.There are several conditions that can cause a dilated pupil, including: Corneal ulcer: An ulcer on the surface of the eye can cause enough pain to result in miosis (constriction of the pupil).ĭilated pupil (mydriasis) as the cause of anisocoria in dogs.Anterior uveitis (inflammation inside the eye): If only one eye is affected, anisocoria will be present as uveitis will result in the constriction of one pupil with the other being a normal size.This can be due to trauma, tumours, or other conditions that affect the nervous system. Horner's syndrome: A condition which is caused by damage to the sympathetic nervous system.There are a few conditions that can cause a constricted pupil, including: Constricted pupil (miosis) as the cause of anisocoria in dogs We'll look at the possible reasons based on whether the constricted or dilated pupil is the problem.

There are several potential causes of anisocoria in dogs. What are the causes of anisocoria in dogs? In some cases, anisocoria can be an indication of an underlying medical condition that needs to be treated. While anisocoria is usually harmless, it is important to have any changes in pupil size evaluated by a veterinarian. Finally, certain medications and toxins can also cause the pupils to dilate or constrict. Another mechanism is the parasympathetic nervous system, which helps to keep the pupils constricted in low light conditions. The most important of these is the sympathetic nervous system, which controls the dilation and constriction of the pupils in response to light levels. There are several mechanisms that regulate pupil size in dogs. However, it is important to have anisocoria evaluated by a veterinarian, as it can sometimes be an indication of a more serious underlying condition. While it can be caused by several possibilities, in most cases it is benign and does not require treatment. What is anisocoria in dogs and what are the mechanisms that regulate pupil sizes?Īnisocoria, or unequal pupil size, is a common condition in dogs.

Dog one pupil larger than other