Get

In Your Inbox

Dogster is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Iris Atrophy in Dogs: Vet-Reviewed Causes, Signs, & Care

dog eyelid closeup shot

Like their human owners, aging pets are subject to numerous eye disorders, including iris atrophy. As the aperture to the pupil, the iris plays a central role in maintaining comfortable vision under changing light intensity. As iris atrophy appears in dogs, warping and apparent damage to this colorful part of the eye can seem strange and worrisome.

Iris atrophy may be common in dogs, but it never fails to catch owners off guard. Although the condition rarely bears significant consequences, it is important to understand and differentiate it from other more troubling issues.

dogster paw divider

What Is Iris Atrophy in Dogs?

The iris is the colorful portion of the eye with an opening in the middle (the pupil). The muscle expands and contracts according to lighting shifts. It narrows in bright light and widens in low light, protecting the retina and allowing for comfortable vision in changing situations.

Iris atrophy occurs when the muscles in the iris start thinning and weakening. The first sign is visible around the pupil’s edge, which gives it an uneven shape. The condition may also appear as holes torn through sections of the iris. As a consequence of the weakening of the muscles, the normal opening and closing function will be affected and the iris’ response to light will be slower and incomplete.

Primary iris atrophy, or senile iris atrophy, is a progressive condition in older pets. There is no cure for this form of atrophy, though it often doesn’t cause significant vision problems for dogs. Dogs can lose the ability to adapt to changing light conditions and may appear more light-sensitive.

You’re welcome to use our images, but we require you link directly to this site for credit (ex. Image from Dogster)

What Are the Signs of Iris Atrophy?

Iris atrophy typically doesn’t appear at similar rates in the left and right eyes, so anisocoria (unequal pupil sizes) is a common sign. Eye color may fade, while the iris can become translucent. The weakened muscle also may not respond quickly to light, leaving the pupil dilated. The pupil’s irregular shape can be called dyscoria, and it has other causes; therefore, any changes in your dog’s pupil shape warrant a vet visit

Vets perform simple ophthalmology tests for atrophy by shining a bright light in the eye to check for holes/misshapen iris edges and to watch for an unusual pupillary reflex response. Retro illumination techniques show clear images of defects within the iris, allowing for more accurate diagnoses.

Additional exams, such as intraocular pressure measurement, eye fundus exam, and ocular ultrasound, may be necessary to check for signs of trauma, cataracts, glaucoma, or uveitis.

What Are the Causes of Iris Atrophy?

Iris atrophy is a naturally occurring condition. It is also called senile iris atrophy, meaning it is an age-related change. Iris atrophy is relatively common in middle-aged and senior dogs. Any dog of any breed can develop the condition.

Toy and miniature dogs, including Miniature Schnauzers, Miniature Poodles, and Chihuahuas, are generally more susceptible.

Husky dog with different eye color
Image Credit: J. Photos, Shutterstock

How Do I Care for a Dog with Iris Atrophy?

Weekly eye checks should be part of your standard grooming practices. Any signs indicating an eye issue warrant an immediate conversation with the vet. While signs of changes may be due to irreversible iris atrophy, your vet must rule out several more severe conditions that could show similar indicators. Annual eye exams are an essential feature of a proper care routine.

Iris atrophy is painless and generally doesn’t cause vision problems. Because the sphincter muscle contracts slowly (or not at all), the eye can let in more light than is comfortable in bright areas. If your dog squints constantly or looks away from light sources, you can help them by setting them up with light-filtering dog goggles or changing the routine.

Walking and playing with your dog outside early in the morning or just after sunset will help them stay active and comfortable.

Always consult a veterinarian to find the best treatment for your dog.

If you need to speak with a vet but can't get to one, head over to PangoVet. It's an online service where you can talk to a vet online and get the personalized advice you need for your pet — all at an affordable price!

PangoVet_Mention-in-Content Savings V1

dogster paw divider

Frequently Asked Questions

How Do You Keep Your Dog’s Eyes Healthy?

There isn’t much you can do about primary iris atrophy, but frequent checks and regular care will keep your dog’s eyes clean while allowing you to proactively approach anything that might seem off.

The following are a few general eye care tips to keep your dog’s sight healthy:
  • Gently wipe eye discharge daily with a soft, moistened washcloth to prevent infection.
  • Keep an eye wash or saline solution handy when you notice any eye irritation.
  • Style excess hair away from the eyes while grooming.
  • Use a harness instead of a neck collar while walking to prevent strain on the neck and eyes if your dog pulls.
  • Keep your dog secure in your car (no heads out the window).
  • Shield your dog’s eyes while applying sprays or during their normal bath.
  • Visit your vet if your dog’s eyes don’t look right.

Understanding your breed’s unique susceptibility to iris atrophy and common eye issues to watch for will be beneficial in keeping them healthy. Inspect your dog’s eyes closely to recognize their unique details while healthy. Any minor change will be easier to spot when you establish a baseline for what’s normal, allowing you to respond with a call to your vet that much quicker.

Can Iris Atrophy Heal Itself?

Iris atrophy is an age-related change and can’t be cured or slowed down its progression. At the same time, it rarely affects your dog’s sight other than making them a bit light-sensitive because they can’t control the amount of light that enters the eye as before.

dogster paw divider

Conclusion

Misshapen and uneven pupils can be a concerning sign, but iris atrophy in dogs is rarely a substantial concern. When iris atrophy develops, there’s little you can do and not much you need to do, as dogs rarely have issues associated with it and they live happy, fulfilling lives with this age-related change.

Still, any change to your dog’s pupil size or shape should spark an immediate eye exam at the vet. If there’s a dangerous condition causing the iris changes, a fast response can make all the difference in avoiding a huge vet bill and saving your dog’s eyesight.


Featured Image Credit: Sabrinasfotos, Pixabay

Want content like this delivered to you?

Sign Up For Our Newsletter

News, insights, expert advice, and everything dog

* By submitting, you agree to our Terms & Conditions and Privacy & Cookies Policy.

How useful was this post?

Click on a star to rate (you can leave written feedback after clicking submit)

Help us improve Dogster for pet parents!

Your feedback really matters.

What did you like about this post? Also how can we improve it?

Join the conversation

Leave a Reply

You’re very welcome to leave a comment or question. Please know that all comments must meet our community guidelines, and your email address will NOT be published. Let’s have a positive and constructive conversation.

Talk With A Vet Online

Peace of mind,
anywhere, anytime

Affordable vet advice

10 Common Dog Grooming Mistakes & Vet-Approved Tips to Avoid Them

Grooming your dog is essential for maintaining their health and appearance. However, there are common mistakes that owners can make during grooming that...

English vs Australian Shepherd: The Differences (With Pictures)

English Shepherds and Australian Shepherds are both wonderful companion dogs that are incredibly loyal to their families. Both dogs are herding dogs with...

Why Do Dachshunds Hate Rain? 5 Potential Reasons & Tips

You can’t blame Dachshunds for hating the rain. It’s not always fun to walk in the rain, and their disdain isn’t unique to...

Lapponian Herder Dog Breed: Info, Pictures, Care & More

One of Finland’s five national dog breeds, the Lapponian Herder was originally used to both herd and guard reindeer. Having a mid-length coat...

More related

Labernese Dog Breed: Info, Pictures, Care & More

A Labernese is a mix between a Labrador Retriever and a Bernese Mountain Dog. This mixed breed is known for being quite large....

10 Best Dog Breeds for Van Life (With Info & Pictures)

Finding the right canine companion is a priority for many shifting to the fulfilling life of a digital nomad. Having reliable company is...

Miniature Dachshund Dog Breed: Info, Pictures, Origin & History

Did you know that the Miniature Dachshund is identical to a regular Dachshund in every way but size? A Miniature Dachshund must weigh...

Are All White Pitbulls Deaf? Vet-Verified Facts & Health Info

All-white Pitbulls are rare, although certainly not impossible to find. They have the same character and characteristics as other Pitbulls, which means they...

Keep reading

8 Vet-Reviewed Signs You Are Underfeeding Your Dog

We all know how important our dog’s diet is to their health and wellbeing. There are mountains of information regarding the perils of canine obesity, and the health problems associated with it. However, we tend to see decidedly less information...

Thin underweight dog

Can Dogs Eat Raw Chicken Feet? Vet-Verified Nutrition Facts & Info

Dog owners must have strong stomachs when they think of the unusual snacks we give our pets, like pig ears, cow hooves, and bully sticks. But can you add raw chicken feet to that list? The mere suggestion may sound...

Dogster-Can-Dogs-Eat Raw Chicken Feet

11 Best Freeze-Dried Dog Foods in 2025 – Reviews & Top Picks

Freeze-dried dog food takes the preparation and the work out of feeding a raw, natural diet. The freeze-drying process preserves more of the original ingredients’ nutrients and retains the natural flavor to make it more palatable for your dog. Freeze-dried...

labrador-retriever-dog-eating

Is Blue Buffalo Made in the USA? What You Need to Know

Blue Buffalo is a famous dog food brand with many recipes for optimal canine health. There are tons of options in recipes, treats, and other supplements. If you have any kitties—they even have quite a comprehensive cat food line. But...

Is blue buffalo made in the USA?

Raised Right Human-Grade Dog Food Review 2025: Veterinarian-Backed Dog Food

In 2016, a new dog food company emerged from one family’s desire to feed their own dogs a better food. Braeden Ruud and his family, concerned about a recent outbreak of dog food recalls, had begun cooking for their pets...

Dogster_Raised Right Human-Grade Dog Food Review

My Dog Ate Moldy Food: What Should I Do? Vet-Approved Facts & Signs Toxicity

If your dog has eaten moldy food—perhaps you didn’t store the food properly, or your dog ate the moldy food from the garbage—it is a cause for concern. Mold can make your dog sick, which is why you should take...

12 Best Canned & Wet Dog Foods in 2025 – Reviews & Top Picks

Feeding our dogs is part of a billion-dollar business. In fact, in the U.S. alone, $42 billion was spent on pet food and treats this year! We all know how vital food is for pets, so finding the right food...

shih tzu dog getting wet food from owner at kitchen

11 Best Wet Dog Food for Huskies in 2025 – Reviews & Top Picks

Every Siberian Husky owner knows that these dogs have tons of energy. Huskies require a quality, high protein diet low in carbs to recharge and refuel, making the decision of what to feed an important task. Huskies are extremely active...

husky eating