When lung cancer metastasizes (spreads), new tumors tend to form in certain places. Although it’s rare, lung cancer can spread to the eyes, causing several types of symptoms that affect vision. For some people, vision changes due to eye metastasis may be the first sign of lung cancer.

In this article, we’ll discuss how eye metastases form and how they’re diagnosed and treated. We’ll also cover what eye metastasis means for your outlook or prognosis with lung cancer overall.

How Do Eye Metastases Form?

“Metastasis” refers to cancer that has spread away from the main tumor (lesion) to other parts of the body. Eye metastases — also known as ocular metastases — form when cancer cells produce new tumors in the eyes. To better understand eye metastases, it helps to know the different structures in the eye.

The sclera is the white part that gives your eyeball its round shape and structure. The uvea (middle of the eye) refers to tissues behind the sclera. They include your:

• Iris — Colored tissue in the center of your eye, which may be a shade of brown, green, or blue
• Choroid — Tissue containing blood vessels that carry nutrients and oxygen to the eyes
• Ciliary body — Tissue behind the iris that changes shape as your eyes focus on different objects

The choroid sits between the sclera and the retina. Your retina is the light-sensitive tissue found at the back of your eyes that’s responsible for producing the images you see.

Lung Cancer and Eye Metastases

Lung cancer can be difficult to diagnose because it usually doesn’t cause symptoms at an early stage. As a result, around half of all lung cancer cases are metastatic at the time of diagnosis.

Lung cancer typically spreads when tumors move into nearby blood vessels or lymph nodes. The cancer cells enter the bloodstream and travel around the body. Eventually, the cells land in another part of the body and begin forming metastases.

Studies show that around 88 percent of eye metastases develop in the choroid. This is likely because the choroid has many blood vessels that can bring lung cancer cells to the eye. Another 9 percent form in the iris, and ciliary body metastases account for 2 percent of cases.

In a 2021 study in the journal OncoTargets and Therapy, researchers wrote that lung cancer is responsible for 21 percent of eye metastases. However, eye metastases are rare in lung cancer overall. Study findings show that 0.1 percent to 7 percent of people worldwide with lung cancer develop tumors in the eyes, according to BMC Cancer. People with small cell lung cancer and lung adenocarcinoma seem to account for most cases.

In 25 percent to 35 percent of cases, doctors find eye metastases before they find lung cancer, according to OncoTargets and Therapy. About 70 percent to 86 percent of people with eye metastases also have metastases in other places.

Common sites that lung cancer spreads to include the brain, liver, bones, and adrenal glands. One report found that about 22 percent to 33 percent of people with choroidal metastases and lung cancer also have brain metastases.

7 Symptoms of Lung Cancer Metastasis to the Eyes

Symptoms of eye metastasis depend on where the tumor is located and how far it has grown into the eye’s tissues. If you have have an eye metastasis, you may experience some of these symptoms:

• Blurry vision
• Vision loss
• Double vision
• Flashing or spots of light in your vision, which may look like lightning or shooting stars
• Floaters or dark shapes that move across your vision and disappear when you look at them
• Metamorphopsia (vision problems that make straight lines look warped or bent)
• Eye redness and pain

Interestingly, studies have found that new tumors tend to form in the left eye more often than in the right.

Some MyLungCancerTeam members have asked others what their symptoms may mean. “My lung cancer has spread to my brain, but the targeted therapy dissolved the small tumors,” one member said. “Now I’m having some light flashes in my eyes and, of course, I’m wondering if that means the tumors are back. Any insights out there?”

Diagnosis of Lung Cancer Metastasis to the Eyes

If you begin experiencing symptoms of eye metastasis, talk to your doctor or oncologist. They’ll refer you to an ophthalmologist — a doctor who specializes in treating eye diseases. An ophthalmologist is different from an optician, who prescribes glasses and contacts to correct vision.

Your ophthalmologist will start by performing a physical exam. They’ll take a look at your eyes using standard ophthalmic tools and ask about your symptoms. To make an accurate diagnosis, your ophthalmologist may order more tests.

Eye Ultrasound

An eye ultrasound uses sound waves that bounce off the eye structures and form pictures for your ophthalmologist to look at. There are two types of eye ultrasounds — A-scan and B-scan. The B-scan looks for cancer in the eyes. This imaging test is done with your eyes closed. Your ophthalmologist will put gel on your eyelids and place the wand on top. You may be asked to move your eyes in different directions.

Optical Coherence Tomography

Another imaging test used to diagnose eye metastasis is optical coherence tomography. This noninvasive test uses a laser to take pictures of your optic nerve and retina. Optical coherence tomography scans are useful for finding tumors in your retina and choroid.

Fine Needle Aspiration Biopsy

If your ophthalmologist can’t confirm whether you have an eye metastasis, they may perform a fine needle aspiration biopsy. This procedure involves using a very thin needle to take a sample of eye fluid to look at under a microscope. A trained expert will look for cancer cells in the sample.

Treatments for Lung Cancer Metastasis to the Eyes

Your ophthalmologist can prescribe several treatments to address your eye symptoms and improve your quality of life. These options are generally divided into local and systemic (bodywide) treatments.

The gold standard for treating eye metastases is radiation therapy (radiotherapy). A radiation oncologist will deliver strong beams of radiation directly to the eyes to shrink tumors. Another option is plaque radiotherapy, in which radioactive implants are placed directly into your eye.

Systemic lung cancer therapies may also help treat eye metastases. If the tumor cells in an eye metastasis have certain gene mutations (changes), your oncologist can prescribe a targeted therapy. Chemotherapy is an option for people who can’t have radiation therapy or targeted therapy.

Ophthalmologists can also inject medications directly into the eyes. Bevacizumab (Avastin) is a protein drug that blocks tumors from making new blood vessels. This cuts off the blood supply to a tumor, causing it to shrink. Studies show that bevacizumab may be useful for treating choroidal metastases from lung cancer.

If medical treatments don’t work, your ophthalmologist may consider removing your entire eye. However, this treatment isn’t usually recommended.

Outlook With Lung Cancer Metastasis to the Eyes

Researchers have looked into how eye metastasis affects the prognosis (outlook) with lung cancer. One small study of 21 people who had lung cancer with eye metastasis found that their median overall survival rate was 12 months. This means half of the people in the study lived less than 12 months and half lived longer. The one-year survival rate was 44.7 percent — after one year, 44.7 percent of participants were alive.

It’s important to note that studies can only give estimates, and every person’s case is unique. Talk to your oncologist to learn more about your outlook with eye metastasis.

Talk With Others Who Understand

On MyLungCancerTeam, the social network for people with lung cancer and their loved ones, more than 12,000 people from around the world come together to ask questions, offer support and advice, and connect with others who understand life with lung cancer.

Has your lung cancer spread to your eyes? How has your oncologist or ophthalmologist treated it? Share your story in the comments below or by posting on your Activities page.