Is Ocular Melanoma Same as Uveal Melanoma?

What are types of ocular melanoma?

• Uveal melanomas: Most ocular melanomas occur in the uvea, which has three parts: the iris, ciliary body, and choroid. About 90% of cases involve the choroid, approximately 6% involve the ciliary body, and 4% involve the iris.
• Conjunctival melanomas: Rarely, ocular melanoma can occur on the conjunctiva, which is the outermost layer on the front of the eye. There are fewer than five cases per million a year.

What causes ocular melanoma?

The exact causes of ocular melanoma are unknown. Genetic changes or mutations in the DNA within melanocytes make the cells grow and multiply uncontrollably, forming a tumor. 

Researchers and doctors are still not clear about what triggers the genetic changes.

What are risk factors for ocular melanoma?

Several factors increase a person’s risk of developing ocular melanoma. Possible risk factors include:

• Fair or pale skin
• Light-colored, blue, or green eyes
• Family history of ocular melanoma
• Growth on or in the eye
• Age 70 years or older
• Dysplastic nevus syndrome, which causes many abnormal moles to grow on the skin
• Mutation in the BAP1 gene
• Certain conditions, such as congenital ocular melanocytosis, melanosis, and neurofibromatosis
• Presence of a dark area on the white part of the eye and eyelid (nevus of Ota)
• Having one or more freckles in the eye (iris nevi)
• Certain occupations, such as welding

Excessive exposure to sunlight and ultraviolet light may also increase your risk of developing ocular melanoma.

What are the signs and symptoms of ocular melanoma?

Some people with ocular melanoma may not have any signs or symptoms, making it difficult to detect. Symptoms of ocular melanoma may include:

• Sudden loss of vision
• Poor or blurred vision
• Loss of peripheral field vision in one eye
• Appearance of a growing dark spot on the iris
• Bulging of the eye
• Changes in eye movement
• Changes in the shape of the pupil
• Displaced eyeball within the eye socket
• Oddly shaped pupil
• Pain and discomfort in or around the eye (rare)
• Seeing dark spots or flashes or specks of light
• Seeing floaters (spots, squiggly lines, or floating objects) in the field of vision
• Watery eyes

Some of these symptoms can be caused by less serious conditions. It is important to see an eye doctor if any of these symptoms occur to find out the exact cause.

How is ocular melanoma diagnosed?

Along with physical examination, medical and family history, and eye exam with dilated pupils, your doctor will analyze the retina and optic nerve using ophthalmoscopy (funduscopy), gonioscopy, and slit-lamp biomicroscopy.

• Fundus imaging or ocular photography: The inside of the eye is photographed with a special camera.
• Ultrasound scan: Sound waves are used to create images of the eye to diagnose ocular melanomas.
• Ultrasound biomicroscopy: This uses high-energy sound waves to create comprehensive images of the front parts of the eye.
• Fluorescein angiography: This evaluates the ocular blood vessels by injecting an orange, fluorescent dye (fluorescein) and then taking a picture with a special camera.
• Optical coherence tomography: Light waves are used to take cross-sectional images of the retina and choroid.
• Biopsy: A small piece of tissue from the tumor is removed, and the cells are examined under a microscope by a pathologist for signs of cancer.

Blood chemistry analysis, liver function tests, X-ray of the chest, as well as computed tomography, magnetic resonance imaging, and positron emission tomography scans may be used to further investigate melanoma.

How is ocular melanoma treated?

Treatment of ocular melanoma depends on several factors, such as the location, size, and type of tumor, as well as your overall health condition. The melanoma is staged based on its spread locally and distally. Treatment options include:

• Surgery: Different surgical procedures include:
  • Iridectomy: Removal of part of the iris.
  • Peripheral iridectomy along with trabeculectomy: Removal of part of the iris and outer part of the eyeball supporting tissues to which melanomas may have spread.
  • Iridocyclectomy: Removal of a portion of the iris and ciliary body.
  • Choroidectomy: Removal of part of the choroid and section of the eyewall.
  • Transscleral resection: Removal of melanoma of the ciliary body or choroid.
  • Enucleation: Removal of the entire eye.
  • Orbital exenteration: Removal of the eyeball and some surrounding structures and tissues inside the eye socket and parts of the eyelid.
• Radiation therapy: Radiation therapy destroys cancer cells and stops them from growing. Different types of radiation therapy include:
  • Brachytherapy, in which small radioactive seeds are anchored into the eye to shrink the tumor.
  • Teletherapy, which generates radiation outside the patient’s body and targets malignant cells in the eye.
  • Proton beam radiation therapy
  • Stereotactic radiosurgery
• Other targeted therapy
  • Transpupillary thermotherapy uses an infrared laser to heat and shrink smaller tumors.
• Cryotherapy: Cancer cells are frozen and killed using liquid nitrogen.

What are survival rates for ocular cancer?

The 5-year survival rate for ocular cancer is approximately:

• 85% if the cancer has not spread from its original site (localized)
• 71% if the cancer has spread outside the eye to nearby structures or lymph nodes (regional) 
• 13% if the cancer has spread to distant organs