Iris Melanoma

What is iris melanoma?

Iris melanoma is a pigmented tumor that develops in the iris. In dogs, this is the most common tumor occurring in the eye.

Although iris melanoma rarely metastasizes in dogs, as it grows it gradually destroys the eyeball. The tumor:

• Obstructs the normal flow of aqueous humor
• Causes internal inflammation of the eye
• Induces high intraocular pressure
• Can result in pain and blindness

What treatment options are available for iris melanoma?

If the tumor is diagnosed in time, laser treatment is an option, which can stop the melanoma from growing further.

Can every iris melanoma be treated with laser?

Unfortunately not. This is why early diagnosis and prompt treatment are very important.

Laser therapy cannot be used if:

• The tumor affects more than 1/4 of the iris
• The tumor is also located in the iridocorneal angle

In these cases, removal of the eyeball is recommended.

What will the eye look like after laser treatment?

After the procedure:

• A brown spot remains on the iris where the tumor was.
• The tumor no longer grows further, since the laser has destroyed the tumor cells.
• The shape of the pupil may change.

Is a single laser treatment enough?

If the tumor was large or thick, further laser treatment may be necessary. This is decided during follow-up examinations.

Iris melanoma in cats

In cats, iris melanoma is generally malignant and has a higher chance of metastasizing.

It is rare for only a small, isolated area of the iris to be affected. In most cases, the tumor diffusely infiltrates the entire iris, so removal of the eyeball is recommended.

Can iris melanoma be treated with laser in cats too?

Only in certain cases. Laser treatment is recommended exclusively for focal, well-circumscribed lesions.

It is important to know that there is currently no scientific evidence as to whether laser treatment does or does not increase the risk of metastasis in cats.