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Iris Melanosis in Cats: Vet Reviewed Signs, Causes & Treatment

Written by: Brooke Bundy

Last Updated on February 6, 2024 by Catster Editorial Team

An orange tabby domestic shorthair cat with iris melanosis or hyperpigmentation in its eyes

Iris Melanosis in Cats: Vet Reviewed Signs, Causes & Treatment


Dr. Lorna Whittemore Photo


Dr. Lorna Whittemore


The information is current and up-to-date in accordance with the latest veterinarian research.

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A cat’s eyes are often their most striking feature. We all know whether our cats have amber or green irises and are fairly familiar with the shape of their eyes and pupils. Iris melanosis is a condition of the iris when the pigment changes, resulting in dark “freckles” across the iris. This is a benign condition that’s caused by the spread of pigmented cells called melanocytes.

However, in some cats, if the abnormal cell reproduction continues, it can lead to transformation into uveal melanoma, a malignant cancer. It’s important to take your cat to the vet as soon as you notice signs of color change in your cat’s eyes so that they can be examined and appropriate treatment given.

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What Is Iris Melanosis?

A cat with iris melanosis develops flat brown pigmented “freckles” on the colored portion of the eye, the iris. The “freckles” are manifestations of the pigmented cells that are abnormally developing in the iris. Most often, the condition is benign and common in adult cats. However, if these abnormal cells continue to multiply, they could eventually transform into malignant cancer. If iris melanosis develops into malignant cancer, it’s then known as feline diffuse iris melanoma or uveal melanoma. This is a cancer of the melanocytes resulting in uncontrolled replication with serious consequences for your cat.

iris melanoma in adult cat
Image Credit: Todorean Gabriel, Shutterstock

What Are the Signs of Iris Melanosis?

The pigmented “freckles” across a cat’s eyes are the first signs of iris melanosis, and they can be single or multiple. If you notice these pigmented spots, you’ll need to take your cat to the vet to determine if they have melanosis or melanoma, which is cancerous. Unfortunately, it can be difficult to know for certain, as in the early stages, the two look the same. It may be necessary for a veterinary ophthalmologist referral for diagnosis and sometimes for a biopsy, but there are some signs that will guide your vet’s diagnosis.

Your vet will check for thickening pigment patches, which is a sign of melanoma. Sudden changes in color or thickness of the iris pigment may indicate cancer, but your vet will also look to see if the shape of the pupil has changed—which would indicate pressure from a tumor or glaucoma. Glaucoma can develop secondary to tumor changes in the eye. Glaucoma is increased pressure within the eye and is a painful condition that needs prompt treatment.

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What Are the Causes of Iris Melanosis?

While iris melanoma can result from iris melanosis, it doesn’t always, and researchers still aren’t sure why. Genetics and environment likely play a role in the development of melanosis and melanoma, but research is still ongoing.

Russian blue cat breed with iris pigmentation
Image Credit: Todorean-Gabriel, Shutterstock

How Do I Care for a Cat With Iris Melanosis

If your cat has developed iris melanosis, there is no specific treatment that needs to be undertaken. However, you should closely monitor the eyes for further changes and re-visit your vet regularly for check-ups. Essential fatty acid supplements are helpful for reducing inflammation and may be recommended by your veterinarian.

If your vet doesn’t think your cat’s condition has transformed into cancer, they may recommend regular checkups and a consultation with a veterinary ophthalmologist.

If your cat has developed glaucoma or cancer, their vision quality has already decreased, and their eye is painful. In this case, the best course of treatment may actually be enucleation or removal of the eye. Melanomas are aggressive cancers that can spread (metastasize) to other parts of the body, and prompt treatment is needed.

While no one wants their cat to lose an eye, it’s sometimes necessary to save their life.

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Frequently Asked Questions

My cat has been diagnosed with iris melanosis. What should I do?

By diagnosing your cat with iris melanosis, your vet is saying that the dark freckles across your cat’s eyes aren’t dangerous…yet. While sometimes the best course of action is to wait and see, you’ll want to keep an eye on your cat’s eyes for any sudden changes. If changes are noted, your vet or veterinary ophthalmologist will guide you through the options available.

What’s the life expectancy for a cat with iris melanosis?

Unless the condition progresses into iris melanoma—which doesn’t always happen—your cat should enjoy the average life expectancy of their particular breed.

vet checking cat's eyes
Image Credit: santypan, Shutterstock



Iris melanosis doesn’t harm your cat by itself, but unfortunately, it can progress to the formation of cancer, which is known as iris melanoma. Your vet will be your best guide in treatment options. In the best-case scenario, the iris freckles will not change, and your cat will live a normal life. On other occasions, there may be transformation to melanoma, and early detection and treatment will give your cat the best chance of a good outcome.

Featured Image Credit: Mary Swift, Shutterstock

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