Why Are My Cat’s Eyes Dilated in Kittery, ME


The cat’s eye…the iris color may be striking, but the pupil, the black part of the eye, gives you information about your cat. In a healthy cat, the pupils constrict and become slit-like in bright light, and dilates to improve their vision by absorbing more light in dim settings. But that isn’t the only time a cat’s pupils dilate.

The cat’s eyes are windows to his health and wellbeing. A cat’s eyes will also dilate when she’s excited, afraid, or injured. Though these situations are not cause for the pupils to remain dilated for more than a couple of hours before going back to normal. Constant dilation of the eyes is a sign that something is wrong. Many health issues are associated with dilated eyes so it’s a concern when they do not return to normal. This article will discuss the implications of cat’s dilated eyes.


When Are Dilated Eyes Normal?

Normal eye dilation occurs:

  • In reduced light. The pupil dilates to let in more light.
  • Emotional response to anger or aggravation, happiness, fear, or excitement.
  • Medications including amphetamine, Atropine, clonidine, morphine, tropicamide.
  • Catnip consumption.
Why Are My Cat’s Eyes Dilated in Kittery, ME

When Aren’t Dilated Eyes Normal?

It isn’t normal for a cat’s eyes to remain continually dilated. When this happens it can indicate:

  • Overstimulation
  • Pain
  • Age-related atrophy
  • A medical condition


Related Health Conditions

There are serious health conditions associated with dilated pupils that don’t contract, including:


This is when a cat’s pupils are two different sizes. It’s a sign there’s an abnormality that could have been caused by infection, trauma, stroke, or tumors. There is a defect somewhere between the brain, nerve pathways, and the eyes. This isn’t a disease but an indicator of something else being wrong.

Brain Tumor

The most common kind of feline brain tumor is a meningioma. This is a benign tumor arising from the meninges (the membrane surrounding the brain and spinal cord.)

Feline Dilated Pupil Syndrome

A rare condition also known as Key-Gaskell Syndrome. A dysfunction of the autonomic nervous system causes this condition. This system regulates the basic, unconscious body functions including the heart muscle, the digestive system, and the pupils of the eyes.


Glaucoma is a condition that happens when pressure in the eye increases to the point that it damages the optic nerve. It’s usually caused by a blockage in the drainage system in the eye. Glaucoma can lead to blindness.


This is a low level of calcium in the bloodstream. Calcium is important in vital functions such as transmission of nerve impulses, bone growth, muscle contraction, and blood clotting.

Head Trauma

Any trauma involving the cat’s head can potentially cause brain damage and affect the autonomic nervous system.


Insulinomas are cancerous, fast growing tissue of beta cells in the pancreas.

Retinal Detachment

A common and sight-threatening disorder of the eye when the retina detaches from the retinal pigment epithelium layer.

Thiamine Deficiency

A vitamin that plays a role in many bodily functions including the nervous system. Thiamine deficiency is rare in cats and is usually tied to a home-made diet.

Venom Toxicity

Sources of venom toxicity are snakes, spiders, and other toxic insects.


What Should You Do?

If you notice your cat’s eyes have been dilated longer than normal, move him into bright light or shine a light into one eye. See if the pupils constrict. If not, call your veterinarian and follow their guidance.


Veterinarian Exam

Your vet will perform a complete exam and may need to run diagnostic testing to uncover the cause.

They will need a medical history if this is your first time at this veterinarian’s office. Prepare to answer questions such as:

  • Is your cat on medication?
  • Has your cat’s vision been affected?
  • Are there other symptoms?
  • Does your cat have any medical conditions?
  • How long have your cat’s eyes been dilated?
  • Did your cat get into any cleaners or chemicals?
  • Do you have toxic house plants?
  • Does your cat ever go outside?


Your cat’s eyes will be carefully examined.

Some diagnostics your vet my order include:

  • Baseline tests (bloodwork, urinalysis, blood pressure, etc.)
  • Ophthalmoscopy, to examine the retina, optic nerve, and blood vessels.
  • Gonioscopy, to examine the eye’s drainage system.
  • Tonometry, to measure the pressure inside the eye for glaucoma.
  • Ultrasound, to evaluate the eyes.
  • CT scan, to evaluate for brain tumors.


Loss Of Vision

When a cat is losing its vision, the eyes will remain dilated as the eyes try to absorb more light in order to see. If you notice your cat isn’t acting normally and displays some or all of the following signs, she may be blind or very near blind.


Signs of feline visual impairment include:

  • Reluctance to jump or climb
  • Squinting
  • Redness around the eyes
  • Milky or cloudy appearance to the eyes
  • May seem unbalanced when walking
  • Difficulty finding water
  • Walking with whiskers low to the ground
  • Frightened by sudden noises
  • Excessive vocalization, distressed
 Cat’s Eyes Dilated in Kittery, ME

There are some simple ways to test your cat’s vision.

  • Use a laser pointer quickly over the floor in front of your cat.
  • Toss cotton balls in front of the cat. A cat will usually play with them.
  • Wave your hand toward your cat’s eyes (not fast enough to generate air flow). They should blink.
  • Shine a bright light in your cat’s eyes. They should respond.


If your cat permanently loses sight, there are things you can do to help.

  • Leave furniture where the cat is used to it being located.
  • Talk to your cat a lot in a soothing tone.
  • Don’t “sneak” up on your cat.
  • Keep obstacles out of your cat’s way.
  • Avoid loud noises.



A cat’s eyes can be dilated for many reasons, from joyful play, a catnip high, to a vision stealing disease. If your cat’s eyes return to normal and don’t remain dilated, then there probably isn’t need for concern. But even if your cat has a condition that causes the loss of vision, she can adapt and have a quality life. Though if you are worried about your cat, call your veterinarian. Many times a simple phone call can relieve your fears with an explanation of what your cat is experiencing.


If your dog is experiencing seizures, please call our vet at (207) 439-2661.