Intraocular Melanoma: Symptoms and Treatment

What is Intraocular Melanoma?

Intraocular melanoma is a rare type of eye cancer that occurs inside the eye. Intraocular melanoma may originate in the middle layer of the eye, which is known as the uvea. While it is considered rare, intraocular melanoma can affect anyone, but may be more common in certain groups of people, according to the Melanoma Research Alliance. Intraocular melanoma is a serious condition, and early detection improves outcomes for patients.

What are the Main Types of Intraocular Melanoma?

The main types of intraocular melanoma are choroidal melanoma, ciliary body melanoma, and iris melanoma. These types of intraocular melanoma are explained below.

• Choroidal melanoma: Choroidal melanoma is the most common type of intraocular melanoma in adults, and arises from the choroid layer of the eye.
• Ciliary body melanoma: Ciliary body melanoma is a rare, malignant tumour that arises from melanocytes (pigment cells) in the eye's uveal tract.
• Iris melanoma: Iris melanoma is a rare, malignant tumour that arises in the iris (coloured part of the eye).

What are the Symptoms of Intraocular Melanoma?

There are various symptoms of intraocular melanoma, including blurred or decreased vision, visual field defect, photopsia, flashes of light, floaters, dark spots on the iris, loss of peripheral vision, pupil shape changes, eye bulging and sudden vision loss. It is worth mentioning that many cases of intraocular melanoma are asymptomatic. A detailed list of intraocular symptoms is provided below.

• Blurred or decreased vision: Blurred or decreased vision in the affected eye is a common symptom of intraocular melanoma, with the patient struggling to see things clearly.
• Visual field defect: Visual field defect refers to areas of lost or reduced vision, blind spots (scotomas), or peripheral vision loss.
• Photopsia: Photopsia refers to a perception of flashing lights or streaks that happens without an actual source of light.
• Flashes of light: Flashes of light can include seeing flashes, streaks or wavy lines.
• Floaters (spots in vision): Floaters refer to tiny specks seen in your field of vision, according to Better Health Channel Victoria. New or increased floaters are sometimes a symptom of intraocular melanoma.
• Dark spot on the iris that enlarges: A dark spot or speck on the iris (the coloured part of the eye) that enlarges in size is a symptom of intraocular melanoma.
• Loss of peripheral vision: A significant loss of peripheral vision, which relates to an inability to see things on the side of your vision.
• Change in pupil shape: A noticeable change in pupil size (distortion) is another intraocular melanoma symptom.
• Bulging of the eye: Bulging of the eye (proptosis) is a symptom of intraocular melanoma, often accompanied by redness and pain. This is only usually seen in late-stage cases.
• Sudden vision loss: Sudden vision loss may occur in intraocular melanoma patients, but it is usually a sign of advanced tumour growth or related to retinal detachment. Sudden vision loss is a medical emergency. If you experience a rapid change in your vision, please contact your optometrist or healthcare professional immediately, or visit the nearest emergency department.

What Causes Intraocular Melanoma?

The causes of intraocular melanoma are not fully understood, but are related to mutations occurring in the pigment cells of the eye. There are various risk factors that are related to intraocular melanoma, including genetic mutations, light-coloured eyes, fair skin or sun sensitivity, older age, ocular melanocytosis, pre-existing eye nevi, BAP1 tumour predisposition syndrome, and possible occupational or environmental exposure. A detailed list of different risk factors for intraocular melanoma is provided below.

• Genetic mutations (e.g., in GNAQ, GNA11, BAP1): Genetic mutations that turn normal melanocytes into malignant tumours are a main risk factor for intraocular melanoma. 'The GNAQ and GNA11 genes are mutated in almost 80–90% of uveal melanomas in a mutually exclusive pattern', according to P. Silva-Rodriguez's research paper titled 'GNAQ and GNA11 Genes: A Comprehensive Review on Oncogenesis, Prognosis and Therapeutic Opportunities in Uveal Melanoma' published in 2022. Mutations in the BAP1 gene are also strongly associated with intraocular melanoma.
• Light-coloured eyes (blue, green, grey): Having light-coloured eyes is a significant and well-documented risk factor for intraocular melanoma, although the reason is not completely clear.
• Fair skin/sun sensitivity: There is a significant risk of intraocular melanoma developing in patients with fairer skin or who are generally more sensitive to the sun.
• Older age (especially over 50): Intraocular melanoma is more common in those over the age of 50, and is rarely found in children, according to the Melanoma Research Alliance, although the exact reason for this is not fully known. It is important to note that the incidence of intraocular melanoma is rare overall, according to Cancer Council Australia.
• Ocular or oculodermal melanocytosis: Ocular or oculodermal melanocytosis is characterised by blue or grey patches on the eye or skin. Ocular or oculodermal melanocytosis is a significant risk factor for developing intraocular melanoma.
• Pre-existing eye nevi: Pre-existing eye nevi are pre-existing benign growths called choroidal nevi (eye moles or freckles) that may develop into intraocular melanoma, specifically uveal melanoma.
• BAP1 tumour predisposition syndrome: BAP1 tumour predisposition syndrome is an inherited condition caused by a mutation in the BAP1 gene that significantly increases the risk of developing specific cancers at a younger age, including uveal melanoma. BAP1 tumour predisposition syndrome is associated with uveal melanoma, according to R. Pilarski's research paper titled 'BAP1 Tumour Predisposition Syndrome', published in 2016.
• Possible occupational/environmental exposure (e.g., welding, chemicals): Possible occupational/environmental exposure, such as welding or exposure to certain chemical solvents, has been linked to the development of intraocular melanoma. A case-controlled study conducted by E. A Holly, D. A Aston, D. K Ahn, and A. H Smith, titled 'Intraocular melanoma linked to occupations and chemical exposures', published in 1996, found an increased risk of uveal melanoma for occupational groups who had intense exposure to ultraviolet light, welding exposure, and asbestos exposure. Although this study suggested a link to occupational exposures like welding, research is ongoing to confirm that these environmental factors are linked to intraocular melanoma.

What are the Treatment Options for Intraocular Melanoma?

The treatment options for intraocular melanoma aim to preserve vision and the eye itself, and include radiation, laser therapies, or surgery. The most common types of these treatments are listed below.

• Plaque Brachytherapy (radiation): Plaque Brachytherapy involves a radioactive disc being temporarily stitched onto the outside of the tumour, usually for 3-7 days, which administers targeted radiation to the tumour.
• Transpupillary Thermotherapy (laser therapy): Transpupillary Thermotherapy (TTT) involves an infrared laser that heats and therefore destroys cancer cells associated with intraocular melanoma tumours. This treatment is often used in addition to radiation rather than as a standalone treatment.
• Enucleation (surgery): Enucleation refers to the removal of the entire eye, which usually only occurs for very large tumours. An iridectomy or iridocyclectomy may be performed, which is the removal of a part of the eye where the tumour is located. Local resection refers to the surgical removal of the tumour itself.

Treatment for intraocular melanoma is managed by specialist ophthalmologists and oncologists. Your optometrist plays a vital role in early detection and referral.

How Can Vision Be Managed After Intraocular Melanoma Treatment?

Vision is managed after intraocular melanoma treatment through corrective lenses, rehabilitation, and targeted therapies. Corrective lenses refer to prescription glasses that can improve clarity, with patients often needing a new prescription to adjust to changes in their vision following treatment. Tinted lenses and sunglasses are also recommended to manage light sensitivity, which is a common side effect of radiation therapy, specifically. Rehabilitation refers mostly to patients who experience permanent vision loss, and includes low vision aids, accessibility tools, and occupational therapy. It is important to note that vision loss after treatment is often due to the location of the tumour or side effects of radiation, rather than the surgery itself. Target therapies that can reduce complications that may follow treatment include anti-vascular endothelial growth factor (anti-VEGF) injections and laser therapy. Regular monitoring is required following intraocular melanoma treatment, including follow-up care to track recovery. Although the management options mentioned above can support daily function, long-term care is needed to support full recovery and optimal eye health.

Intraocular melanoma is a complex condition, and every patient's recovery journey is unique. It is essential that you consult your ophthalmologist or eye care professional before starting any new treatment or rehabilitation program. Only a qualified specialist can provide a tailored management plan based on your specific clinical history and response to therapy.

How Can Light Sensitivity Be Reduced in Intraocular Melanoma Patients?

Light sensitivity may be reduced in intraocular melanoma patients by using UV protective eyewear and lenses, environmental adjustments, and medical interventions. Protective eyewear and lenses include polarised sunglasses, wraparound sunglasses, specialised tints, and photochromic lenses to reduce glare and protect the eyes from harmful UVA and UVB rays. Blue light filters can help reduce eye strain caused by digital screens and artificial lights. Environmental adjustments include limiting bright exposure and using control lighting where possible, such as dimmer switches. Patients may also find it helpful to avoid fluorescent lights and use diffusers to spread light to make it less intense. Medical interventions involve the use of lubricating eye drops to maintain moisture in the eyes and lessen the effects of light sensitivity. Symptom relief for intraocular melanoma patients is important and supports daily function and well-being.

What Vision Problems Can Intraocular Melanoma Cause?

Intraocular melanoma can cause various vision problems, including blurred vision, loss of peripheral vision, partial or complete loss in one eye, seeing flashes of light, floaters, distorted vision, dark spots, reduced visual acuity, double vision, pupil size changes and increased light sensitivity. A detailed list of vision problems caused by intraocular melanoma is provided below.

• Blurred vision: Blurred vision is a common vision problem caused by intraocular melanoma. It involves poor vision in the affected eye, which can be blurry or hazy.
• Loss of peripheral (side) vision: Loss of peripheral vision describes loss of side vision, which can make it difficult to see things on the side.
• Partial or complete vision loss in one eye: Partial or complete vision loss in one eye is a serious vision problem caused by a severe case of intraocular melanoma.
• Seeing flashes of light (photopsia): Seeing flashes of light, also known as photopsia, is a recognized vision problem associated with intraocular melanoma. It is often described as lightning streaks or shooting stars in the field of vision.
• Floaters (spots or shapes drifting in vision): Floaters are tiny specks, spots, or wavy lines that are a common vision problem associated with intraocular melanoma.
• Distorted vision (straight lines appear wavy): Distorted vision where straight lines appear wavy or curved is a vision problem linked to intraocular melanoma.
• Dark spots or shadows in the visual field: Dark spots or shadows in the visual field, including floaters and other visual disturbances, are a common vision problem caused by intraocular melanoma.
• Reduced visual acuity: Reduced visual acuity relates similarly to blurred or generally poor vision, often caused by intraocular melanoma. Objects may appear blurry, hazy, or out of focus.
• Double vision (less common): Double vision, or diplopia, is a less common vision problem caused by intraocular melanoma, where the patient may experience the perception of two images of a single object, either horizontally, vertically, or diagonally.
• Changes in pupil shape or size: Changes in pupil shape or size are a common visual side effect that can affect intraocular melanoma patients. The pupil may become larger as the cancer affects the iris, or it may become distorted, ragged, or asymmetrical.
• Increased light sensitivity (photophobia): Increased light sensitivity, or photophobia, is a less common symptom than flashing lights, but it may occur particularly if the tumour causes inflammation or irritation.