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Overview of Hong Kong
Eye cancer mainly indicates retinoblastoma, which is a relatively rare form of eye cancer typically found in young children and rarely seen in adults.
Among children specifically, retinoblastoma is the most common type of cancer, accounting for about 2% of all childhood cancer cases. However, according to data from the American Cancer Society, only around 200 to 300 children are diagnosed with retinoblastoma annually in the United States, indicating that this disease remains relatively uncommon overall.
Additionally, the society’s data shows that retinoblastoma predominantly affects very young children, with the average age at diagnosis being just 2 years old. Cases in children over 6 years of age are sporadic. Apart from age, the occurrence of eye cancer appears relatively random, with similar incidence rates between boys and girls and across different ethnic groups.
Eye cancer can affect one or both eyes. Among diagnosed retinoblastoma cases in the U.S., approximately 75% involve cancer in one eye, while the remaining 25% involve both eyes. The likelihood of cancer developing in the left or right eye is nearly equal.
Among various cancers, eye cancer is relatively more straightforward to treat, with over 9 out of 10 diagnosed patients in the U.S. achieving successful recovery. However, effective treatment depends on the cancer being confined to the retina. Once it spreads beyond the eye, the prognosis becomes less optimistic.
Retinoblastoma primarily develops due to genetic mutations in the retinal nerve cells, leading to rapid proliferation and destruction of healthy cells, eventually forming a tumour. In most cases, the cause of these retinal gene mutations is unknown, though they may be inherited from parents. Retinoblastoma is inherited in an autosomal dominant pattern, meaning if either parent carries the mutated gene, their child has a 50% risk of developing the disease. Additionally, children with inherited tumours have a 50% chance of passing the gene to their offspring, while those with non-hereditary tumours generally do not transmit the gene.
While risk factors for most cancers are linked to lifestyle habits that accumulate over time, this is not the case for retinoblastoma, which predominantly affects young children. Apart from age, children themselves have almost no associated risk factors for this cancer; instead, it largely depends on their parents. Children may have a higher likelihood of developing retinoblastoma if their parents meet the following conditions:
It is worth noting that, aside from age, these risk factors do not necessarily lead to eye cancer, and their exact relationship requires further medical research.
Eye Cancer Symptoms
Since retinoblastoma primarily occurs in young children, its symptoms are often difficult to detect. However, the following signs may indicate the possibility of the disease:
Other possible symptoms include eye redness, pain, bleeding, uneven iris colour, and pupils that do not constrict in response to light. Parents who notice these signs, observe other abnormalities, or have a family history of the disease should seek medical attention promptly. Even if doctors determine it is not retinoblastoma, any issues with a child’s vision should be diagnosed and treated early to preserve healthy eyesight.
Common Diagnostic Methods
Unlike other cancers, retinoblastoma does not require a tissue biopsy for diagnosis, as this tumour is visually distinct from different eye conditions. Biopsies may risk damaging the eye or spreading cancer cells.
The primary diagnostic methods for retinoblastoma include:
After diagnosis, retinoblastoma is internationally classified into five stages based on disease severity and treatment success rates.
| Stage | Description |
| A | Small tumours no larger than 3mm in diameter remain confined to the retina. They are located away from critical structures such as the optic disc (where the optic nerve enters the retina) and the fovea centralis. |
| B | Tumours of any size are located anywhere on the retina, even if they are larger than 3mm or near the optic disc or fovea centralis. |
| C | Clearly defined tumours with minimal spread beneath the retina or formation of vitreous seeding (gel-like tumour cells in the eye). |
| D | Large or poorly defined tumours with extensive spread into the vitreous humour or beneath the retina, potentially causing retinal detachment. |
| E | Massive tumours that extend to the front of the eye, cause bleeding, lead to glaucoma, or show any signs indicating the eye cannot be saved. |
Primary Treatment Methods
The optimal treatment approach for childhood retinoblastoma depends on tumour size, location, extent of spread, and the child’s overall health condition. Standard treatment methods include:
A laser destroys blood vessels supplying oxygen and nutrients to the tumour, killing cancer cells.
Extremely cold substances like liquid nitrogen are applied near the cancer cells to freeze them. The frozen tissue is then allowed to thaw. Repeating this process several times effectively kills the cancer cells.
If the retinoblastoma is too large and other treatment methods are limited in effectiveness, surgical intervention becomes necessary to obliterate the cancerous cells. The doctor will first sever the muscles and tissues surrounding the patient’s eye, then remove the eyeball along with the optic nerve connected to the brain. A plastic prosthetic eye is immediately implanted and attached to the muscles controlling eye movement, though this artificial eye does not provide vision. The patient will be fitted with a custom-made artificial eye several weeks later.
Healthy Living
After a child undergoes treatment, the doctor will schedule a series of follow-up examinations to monitor potential side effects and the possibility of cancer recurrence. New tumours may develop around 3 to 4 years after successful treatment, particularly for patients with hereditary retinoblastoma. Therefore, patients must adhere to the doctor’s instructions and undergo regular eye examinations. If no abnormalities are detected over time, the frequency of check-ups can gradually be reduced. For patients who have undergone eye removal, regular examinations are also essential to monitor the risk of cancer recurrence or spread, as well as any other post-surgical complications.
Prevention Methods
Since the exact cause of retinoblastoma remains unclear in the medical field, defining prevention methods is challenging. For hereditary retinoblastoma, prevention is nearly impossible. Parents can only ensure their children undergo early eye examinations to determine their risk of developing eye cancer. Even if a tumour is detected, early treatment is still possible.
Additionally, if doctors suspect a hereditary genetic mutation causes a child’s eye cancer, the family may need genetic testing. This helps assess the child’s risk of developing other cancers, the likelihood of siblings developing cancer, and the chances of parents passing the mutated gene to future children.
Frequently Asked Questions
In terms of occurrence, retinoblastoma is relatively rare and primarily affects young children, with similar risks across different ethnicities. In contrast, ocular melanoma, a more common type of eye cancer, can occur at any age, with risk increasing with age and a higher prevalence among white individuals.
Regarding symptoms, both conditions often lack obvious early signs. In some retinoblastoma cases, symptoms may include a white pupil under light, strabismus (crossed eyes), eye pain, or uneven iris colour. Possible signs of ocular melanoma include dark spots on the iris, irregular pupil shape, blurred vision, or loss of peripheral vision.
As parents, receiving a cancer diagnosis for your child is understandably distressing. However, to avoid affecting their emotional well-being and to ensure they receive the most appropriate and effective treatment, it’s essential to stay calm and seek professional medical advice. Discuss the cancer’s status, disease progression, and the pros and cons of different treatments to make informed decisions. Confide in trusted family or friends to maintain a positive mindset while caring for your child.
Retinoblastoma can recur in the initially affected eye or surrounding areas. Children with hereditary retinoblastoma also face a higher risk of developing other cancers. Therefore, doctors may schedule follow-up treatments spanning several years, and regular eye exams are essential to detect any new issues early.
As mentioned, over 90% of retinoblastoma patients in the U.S. recover successfully, so parents need not worry about permanent vision loss. However, early diagnosis and treatment are crucial. Parents should monitor their child’s eye health and seek medical attention promptly if abnormalities or discomfort arise.
Depending on the patient’s condition, doctors will arrange follow-up exams and treatments to control cancer growth and spread, alleviating symptoms even if a complete cure isn’t possible. In such cases, parents and patients should avoid excessive anxiety, follow medical advice strictly, and minimise the cancer’s impact. Social workers can also provide support if needed.
▣ The information on this website has been reviewed by the HEAL Medical Team and is regularly updated according to the most recent clinical evidence. All content is provided for general informational purposes only and should not replace professional medical advice. Please consult your doctor or another qualified healthcare professional for personalized medical guidance.
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