Any cancer that begins in the eye is referred to as eye cancer. Eye cancer can develop in one of three areas of the eye:
- The eyeball (globe) is made up of three layers, namely the sclera, the uvea, and the retina, and is filled with a jelly-like substance called the vitreous humour.
- The orbit, which comprises the tissues surrounding the eyeball
- The eyelids and tear glands, which are accessory structures.
Melanoma is the most common form of eye cancer, and it is predominant among adults. Other types of cancer, however, form in other parts of the eye.
Intraocular malignancies (cancers within the eye) are cancers that affect the eye itself. Primary intraocular malignancies begin in the eye and spread from there. Primary intraocular malignancies in adults include:
1. Melanoma: Melanomas arise from melanocytes, pigment-producing cells. Melanoma commonly develops in the uvea (uveal melanomas) rather than the conjunctiva (conjunctival melanomas).
2. Primary Ocular Lymphoma: This type of lymphoma can develop in the retina as well as the vitreous of the eye. The back of the eye’s optic nerve is also affected. Non-Hodgkin’s B cell lymphoma is the most common type of primary ocular lymphoma.
The following are the most prevalent primary intraocular malignancies in children:
1. Retinoblastoma: A malignancy that begins in retinal cells (the light-sensing cells in the back of the eye).
2. Medulloepithelioma: This is the second most prevalent type of cancer, but it is still quite uncommon.
The external tumours are usually benign and slow-growing and can be treated with simple excision. Internal tumours of the retina and choroid are more dangerous, and they frequently require radiation and other treatments in addition to surgery. Adults can develop intraocular melanoma, and children can develop retinoblastoma, both of which can spread to other organs.
Many common malignancies, such as breast and lung cancer, can spread to the eyes as well. These are called secondary intraocular malignancies.
Unless cancer has spread to certain areas of the eye or has progressed, eye melanoma is asymptomatic. Many of these symptoms can be caused by other, less serious illnesses. Following are the key symptoms of eye cancer:
- Sudden vision loss or blurry vision
- Floaters (spots or squiggles drifting in the field of vision) or flashes of light
- Change in pupil’s size and shape
- Change in eyeball’s position within its socket
- A spreading black spot on the iris
- Bulging of the eye
- Changes in the eye movement within the socket
- Rarely, pain is also seen if the tumour has grown extensively outside the eye.
The cause of the majority of eye malignancies is unknown. However, the researchers have identified certain factors that increase one’s risk of developing eye cancer:
- Eye Colour: People with light-coloured eyes, such as blue, green, or grey eyes, are found to be more prone to develop melanoma of the eye than people with brown eyes.
- Moles: Moles are also on the list of risk factors. Melanoma of the skin and eyes is more likely in people who have moles.
- Skin Colour: Having a light skin tone is thought to be one of the factors that contribute to the development of eye cancer.
- Compromised Immunity: People who have been infected by viruses like AIDS or the Human Papillomavirus, or who have autoimmune illnesses like rheumatoid arthritis are at a higher risk of developing eye cancer.
- Exposure to UV Radiation: Prolonged exposure to UV light may increase eye cancer risk.
- Immunosuppressants: Usage of Immunosuppressants is also touted to be a risk factor for eye cancer.
An examination of the eye is frequently the most crucial first step in diagnosing eye cancer. The doctor may ask about the symptoms while inspecting the eye for vision and eye movement. The doctor will also examine the outside of the eye for swollen blood vessels, which could indicate the presence of a tumour inside the eye.
Specific instruments may be used by the ophthalmologist to have a good look inside the eye for a tumour or other problem.
a. Ophthalmoscope: An ophthalmoscope is a hand-held tool with a light and a small magnifying lens that is used to examine the eyes.
b. Indirect Ophthalmoscope: This type of ophthalmoscope is stationary on a platform and has a higher magnification for a more detailed look.
c. Gonioscopy Lens: A gonioscopy lens, which is a special mirrored lens, is used to detect tumour growth in parts of the eye that are difficult to notice otherwise. During the test, the gonioscopy lens is placed on the cornea layer after it is numbed and the insides of the eye are carefully observed.
If there are any abnormalities found during the above tests, then additional tests may be recommended for a conclusive diagnosis.
d. Imaging Tests: Ultrasound scans, fluorescein angiography, CT scans, X-Rays, and MRI scans are used to diagnose eye cancers. They provide useful information, such as tumours’ size, location, and shape, as well as any swollen lymph nodes around the eyes. Cancer cells may be present in these lymph nodes.
e. Biopsy: A fine needle is usually used to aspirate some vitreous fluid from within the eye during a biopsy. Under a microscope, the sample is checked for cancer cells.
f. Lumbar Puncture or Spinal Tap: Because eye lymphomas can be an extension of CNS lymphomas, a spinal tap to evaluate the cerebrospinal fluid may be necessary. Because the CSF bathes the brain and spine, it could reveal signs of lymphoma in the spine or brain.
g. Bone Marrow Test: A bone marrow examination may be performed to rule out lymphoma spread to other areas.
Treatment recommendations for eye cancer management are made upon taking many factors, such as location and size of the tumour, how far the tumour has spread and the patient’s overall condition. Surgery is the first line of treatment for eye cancers. Other treatment options include laser surgery, radiation therapy and chemotherapy.
a. Surgery: Surgery involves the removal of the tumour along with a small portion of the healthy tissue surrounding it; however, if the cancer is in the advanced stage, the entire eyeball may have to be removed. There are multiple surgical approaches to manage eye cancers.
- 1. Iridectomy: Iridectomy is the surgical removal of a portion of the iris. This could be a possibility for small iris melanomas.
- 2. Irido Trabeculectomy: A portion of the iris and a little amount of the outer section of the eyeball are removed. Small iris melanomas may be successfully treated with this treatment.
- 3. Iridocyclectomy: A piece of the iris and ciliary body are removed. This procedure is also helpful in the management of small iris melanomas.
- 4. Trans-scleral Resection: This procedure involves the surgical removal of the ciliary body or choroidal melanoma.
- 5. Enucleation: Enucleation is a surgical procedure where the entire eyeball is removed. This is usually reserved for larger melanomas, however, it may be utilised for some smaller melanomas if vision has already been lost or if alternative treatment choices would otherwise damage effective vision in the eye. An orbital implant is frequently implanted to replace the eyeball during the same procedure. Silicone or hydroxyapatite is used to create the implant (a substance similar to bone). It is connected to the muscles that moved the eye, thus it should move in the same manner as the original.
- 6. Orbital Exenteration: The eyeball and several surrounding components, including the eyelid and muscles, nerves, and other tissues inside the eye socket, are removed during orbital exenteration. This is not a typical procedure; however, it may be performed in the case of metastasised melanomas.
b. Radiation Therapy: High-energy x-rays are used in radiation therapy to kill cancer cells. It is one of the commonly preferred treatment options for melanoma of the eye. Radiation therapy can often save a person’s vision. There are two approaches to deliver the radiation.
- 1. Brachytherapy: Brachytherapy is a type of radiation therapy in which the doctor places microscopic seeds of radioactive material into or near the tumour. The radiation source being closer to the tumour helps in better targeting and reduced damage to the surrounding tissues. For most eye melanomas, brachytherapy is recommended.
- 2. External Beam Radiation Therapy: In this procedure, radiation is directed towards the tumour from a source outside the body. Today, advanced technologies, such as proton therapy and stereotactic radiosurgery are available and can facilitate superior precision radiation delivery.
c. Laser Therapy: When surgery or radiation therapies are feasible, laser therapy may be used to treat eye melanoma. The following laser therapies are used to treat eye cancer:
- 1. Transpupillary Thermotherapy: This treatment employs infrared light to heat the tumour and kill the tumour cells.
- 2. Laser Photocoagulation: This procedure burns cancer tissue with highly focused, high-energy laser beams.
d. Chemotherapy: Melanoma does not usually respond effectively to conventional chemotherapy agents. Chemotherapy is recommended only after cancer has spread to other parts. If chemotherapy is administered, the treatment is similar to that for cutaneous melanoma.
Frequently Asked Questions
1. Are eye cancers treatable?
Yes, eye cancers are one of the most easily treatable cancers. Nevertheless, early detection becomes important. The five-year survival rates for eye cancers are extremely promising – thanks to the wide range of treatment options available.
It is important to note that eye cancer symptoms mimic those of other less serious eye problems and are often paid less attention. This must be avoided. Any symptom that lasts for more than two weeks should be brought to the physician’s attention without fail.
2. What age is eye cancer most common?
Primary intraocular melanoma is most common among individuals over the age of 50. The average age at which an individual may get diagnosed with eye cancer is 55. It is uncommon in children and those over the age of 70.
3. Can eye cancers be detected in early stages?
Unfortunately, there is no standard screening procedure available for eye cancer that can help in detecting eye cancers in their early stages.
A few eye specialists recommend yearly eye exams which may help in detecting any eye-related abnormalities and planning timely interventions. Melanomas are often caught during routine eye exams.
Also, eye cancers may not show any symptoms in the initial stages, and if they do occur, there are chances of them going unnoticed. Therefore, it is important not to ignore any symptoms and get them checked on time.
4. Does eye cancer come back?
In rare cases, eye cancers can relapse years after treatment, and therefore, it’s important for you to attend all of your follow-up appointments. Follow-up is essential to monitor for cancer recurrence or spread.
5. Can I prevent eye cancer?
Although there are no measures to prevent eye cancers completely, there are a few things that you can do to bring down your eye cancer risk.
Limit your exposure to direct sunlight, wear protective clothes and hats in the sun, use sunscreen and wear wraparound sunglasses with maximum UVA and UVB absorption to protect your eyes.
Although no link has been reported between sunlight and ocular melanomas, some doctors believe that wearing sunglasses can bring down the risk of eye cancers.