Causes and Treatment of Brown Spots on Eyes (Nevi)

Nevi are harmless brown spots that may form on different parts of the eye. Sometimes there is only one and then it is called a nevus, or an eye freckle. You’ll barely experience any discomfort or vision problems when you have a nevus. The lack of symptoms explains why some nevi findings are incidental.

Despite their benign nature, brown spots on the eye require ongoing ophthalmologic monitoring. Some seemingly harmless nevi can develop into vision-threatening eye cancer.  It can affect the colored part of your eye (iris), the transparent tissue layer around your eyeball (conjunctiva) or a tissue layer under the retina on the back of your eye (choroid).

Remember that most nevi are nothing to worry about. The causes can vary from a genetic predisposition to too much sunlight. There are treatments such as radiation, lasers or even surgery.

Causes

Eye freckles form in different ways and sometimes you are born with factors that can bring on these types of growths. The cellular composition of nevi provides the first vital clue as to what their cause could be. In a typical nevus exam, your ophthalmologist will be looking for a cluster of melanin-producing cells, called melanocytes, on the affected part of your eye.

Melanin is a naturally occurring color pigment so any unusual melanocyte buildup can cause visible discoloration or brown spots.

Possible explanations for why this affects some and not others include:

• High melanin levels: Some people, especially Blacks, have higher-than-normal amounts of melanin in the body. They are more likely to be born with the brown spots on the sclera, the white part of the eye.
• Sun exposure: A mass of melanocytes can form on your eyes later in life, causing brown or dark spots. Eye doctors believe exposure to ultraviolet light may be a factor for this type of nevi.

Treatments

Eye freckles are removable. But their largely benign nature makes any medical intervention unnecessary.

The most viable treatment options include:

• Radiation (special equipment delivers appropriate doses of high-energy rays into your eye growth to kill or shrink it)
• Surgery (surgeon cuts into the eye to extract the growth)
• Laser therapy (similar to radiation but designed to heat and destroy it)
• Eye removal (worst- case scenario)

Depending on how deep or extensive the surgery, it could cause unintended damage to the tissues around the affected part of your eye. Your ophthalmologist will not recommend it unless there is a significant risk of the nevus progressing to cancer.

This is also true for laser therapy and radiation. Exposing your eye to high-energy beams to remove non-vision or non-life-threatening discoloration wouldn’t make sense.  

Are These Spots Cancer?

Nevi are not cancer, although they have certain similarities with eye melanoma, a type of cancer.

A non-cancerous nevus usually has the following features:

• Doesn’t increase in size or spread over time
• Tends to be flat, rather than elevated
• Tends to have well-defined margins

Also, any nevi you’re born with are unlikely to transform into cancer.

Are Nevi Dangerous?

Eye freckles are inherently harmless and rarely develop into cancer. The probability of a choroidal nevus turning into cancer is 1 in 8,845.

However, you’re at a higher risk for your brown spots progressing to cancer when you’re older. At 80 years old, the probability is 0.78 percent.

The possibility of any nevus becoming eye melanoma remains real so continuous monitoring after a diagnosis is very important. Once your ophthalmologist confirms that you have a nevus, they’ll take and record an image of the growth. You’ll not need any treatment if the growth is benign at this stage.

But a second nevus exam in about six months may be necessary to closely track any changes. If the growth keeps getting bigger, it may be an eye melanoma.

Other suspicious indications for malignant eye growth include:

• Nevus leaks fluid
• Nevus is raised (not flat)
• Nevus is orange

With close monitoring, your ophthalmologist may provide a conclusive diagnosis for your eye freckles in less than two years. They will intervene, if necessary, to prevent the growth from turning cancerous.

Unlike nevi, eye melanoma is a more serious life-threatening condition. It can cause complications such as:

• Optic nerve damage (glaucoma), which can quickly cause vision loss
• Eye melanoma can spread to other parts of the body.
• Retinal damage, causing vision loss

When to See a Doctor

You can spot certain types of nevi by looking in the mirror. But you still need to see a qualified eye care specialist for a real diagnosis.

A potentially malignant nevus can change rapidly from an initially flat profile to an elevated mass on your eye. It can occur between checkup appointments, hurting your vision.

Seek medical help immediately if you experience sudden vision changes. Alarming issues may include:

• Eye pain
• Change in nevus size
• Change in nevus shape, such as from flat to raised
• Blurry vision
• Flashes of light

FAQs

Why do I have brown spots on my eye?

Brown spots on eyes, or eye freckles, may form when color pigment cells cluster on a spot in your eye. These can either be harmless or potentially a cancerous tumor.

What do brown spots on sclera mean?

Brown spots on sclera, or the white part of the eye, appear when melanin-producing cells accumulate on a part of the eye. Although this anomaly is generally harmless, it can develop into eye melanoma, a type of cancer.

How do I get rid of dark spots on my eyes?

You should see your eye doctor for a proper diagnosis if you notice nevi or dark spots on your eyes. These wouldn’t require treatment unless your doctor thinks they’re likely cancerous.

Treatment options to remove nevi include surgery, lasers, radiotherapy and eye removal.

References

1. Nevus (Eye Freckle). (January 2022). American Academy of Ophthalmology.

2. Why Are the Whites of My Eyes Discolored? (January 2022). American Academy of Ophthalmology.

3. Distinguishing a Choroidal Nevus From a Choroidal Melanoma. (February 2012). American Academy of Ophthalmology.

4. Eye Melanoma. (July 2020) Mayo Clinic.