The dilated pupils in our dog, whether they affect one eye or both, is not normal Therefore, they are not a sign that it can be left without veterinary care. There are multiple causes that can explain the pathological dilation of the pupils. Some are physical, such as trauma or eye problems, while others indicate a psychological problem, as we will see in this article on our site.
In any case, the veterinarian will be the professional in charge of establishing the diagnosis, treatment and referral to the ethologist, if applicable. Keep reading if you want to know more about the dilated pupils in dogs, as well as their causes and treatment.
What do dilated pupils in dogs mean?
The pupil is the round hole located in the center of the eye and is included in the iris, which is a muscular, elastic and contractile membrane that opens and closes toregulate the amount of light that strikes the eye. The iris is pigmented, which is what gives the eye its color. Its operation, therefore, is like that of the diaphragm of photographic cameras. The light enters the eye through different parts, such as the cornea, the anterior chamber, the pupil, the lens, the vitreous chamber and, finally, it reaches the retina, which is responsible for transforming the light into electrical impulses with its cells. photoreceptors. These impulses are the ones that reach the brain from the optic nerve.
Dogs' pupils are large in size and provide a wide field of vision. This allows them to track moving objects very effectively. Therefore, pupils dilate for the following reasons:
- To capture more light.
- In certain emotional situations.
- Due to various pathologies.
- At the time of death.
Pupil dilation is also called mydriasis and can be unilateral or bilateral. Normal pupils are symmetrical and dilate and contract depending on the light.
My dog has a dilated pupil in only one eye
Pupils that are dilated in dogs or that have lost symmetry, which is called anisocoria in dogs, can indicate a brain injuryand have a serious prognosis. Whether the dilation is present in one or both eyes gives the vet clues about the possible cause. Therefore, it is essential to go to the vet.
In addition to brain injury, anisocoria can be caused by a cervical spinal injury or an eye problem Damage of this type can occur when the dog suffers a head injury, for example, a very strong blow, a run over or a fall from a great height.
When assessing the origin and characteristics of a trauma of this type, it is important to make a detailed examination of the dog, performing a neurological examination and diagnostic imaging techniques that are necessary. The prognosis is reserved and, in the most serious cases, the dog dies These are, of course, veterinary emergencies.
My dog always has dilated pupils
Sometimes the cause of dilated pupils in dogs is in the eye itself. If the dog has dilated pupils and cannot see, it may have SARD, which is sudden acquired retinal degeneration This is a disease that damages the retina and causes sudden permanent blindness.
The first sign is bilateral mydriasis. A retinal detachment is also a cause of sudden blindness. These types of cases require consultation with a veterinarian specialized in ophthalmology to assess possible treatment options.
In this other article we explain how to tell if a dog is blind?
My dog has dilated pupils and trembles
If your dog has dilated pupils and trembles, it may be due to these causes.
Dilated pupils in dogs due to poisoning
Sometimes, dilated pupils in dogs are due to poisoning, although it is not the most common symptom, which are usually seizures or hypersalivation.
For example, ivermectin poisoning causes mydriasis, tremors, depression, incoordination, vomiting, etc. Some breeds, such as the collie, are sensitive to this substance. This is a veterinary emergency.
As an emergency, in this other article we explain how to treat a poisoned dog?
Dilated pupils in dogs - psychological disorder
Other times, dilated pupils do not indicate a physical problem, but a psychological one. In these cases, the dog usually suffers from a stress picture that can manifest itself as a phobia or as a compulsive disorder or OCD.
A dog experiencing a phobia, exhibiting mydriasis, tremors, panting, hypersalivation, urination, defecation, etc. Phobias can be resolved with the appropriate behavioral treatment.
Obsessive-compulsive disorder or OCD in dogs
For its part, obsessive-compulsive disorder in dogs is characterized by the presentation of stereotypies, that is, repetitive behaviors that develop always in the same way, meaningless at the time or the environment in which they are performed. They are, for example, biting their tail, turning in a circle, compulsively licking the same place on the body, pretending to capture something with their mouth, etc. But, in addition, physical disorders such as tachycardia, mydriasis, anorexia or diarrhea may occur.
Before diagnosing a CT or psychological problem, the veterinarian must rule out physical problems. Once the diagnosis is confirmed, treatment should be left to dog behavior experts, such as specialized veterinarians, dog educators or ethologists.
