March 18, 2026, 7:58 am | Read time: 9 minutes
Eye cancer—also known medically as “retinoblastoma”—is a rare eye disease. It occurs almost exclusively in childhood and can affect one or both eyes. One of the most common initial symptoms is a white reflection of the eye in flash photos, contrasting with the usual red reflex or dark pupil seen in healthy eyes. Because the cancer grows very quickly, it is particularly dangerous.
What Is Eye Cancer?
Retinoblastoma is a rare form of cancer that originates in the retina of the eye. It most commonly occurs in children under two years old. Particularly insidious: The cancer can affect one or both eyes. It is referred to as unilateral retinoblastoma when only one eye is affected. The majority of cases are unilateral, while about 30 to 40 percent of children develop bilateral retinoblastoma. In this case, it is almost always associated with a genetic (hereditary) mutation. However, some unilateral retinoblastomas can also be genetically determined.
Additionally, the cancer can occur at a single site in the eye (unifocal) or at multiple sites (multifocal). Hereditary forms often present with multiple tumors—frequently in both eyes or newly emerging during the course of the disease.1
Characteristics of Retinoblastomas
The danger of retinoblastomas lies in their rapid growth and ability to spread within the eyeball, into the eye socket, or along the optic nerve to the central nervous system. Especially in advanced stages, they can spread through the bloodstream and along the optic nerve to other organs. If left untreated, the disease can be fatal.
Frequency of Eye Cancer
Although retinoblastoma is considered a rare tumor disease in Germany, it is the most common eye tumor occurring in childhood. Statistically, the disease appears with about 47 new diagnoses per year in approximately one in 18,000 newborns. Nearly all affected children are younger than five years, with the average age of onset being around one year.2
Causes of Eye Cancer
The development of retinoblastoma is caused by two genetic changes (mutations) in the RB1 gene in the precursor cells of the retina. A tumor can only develop when both gene copies are affected. The genetic changes can occur spontaneously in individual retinal cells or be present in all body cells from birth. The latter requires that it be an inherited or early developmental mutation.
Generally, a distinction is made between non-hereditary and hereditary forms.
- Non-hereditary form: The non-hereditary form affects about half of all retinoblastoma patients. The mutations occur exclusively in the tumor cells and do not affect other body cells.
- Hereditary form: In this case, the mutation is present in all body cells from birth and can either be inherited from a parent or newly arisen. If a parent carries the mutation, there is a 50 percent chance it will be passed on to the child. In most of these cases, the child develops retinoblastoma in early childhood. Especially in children with bilateral retinoblastoma, the disease is hereditary.3
Familial Retinoblastoma
In some hereditary cases, other diseases within the family are also known. This is referred to as familial retinoblastoma. However, hereditary retinoblastoma often occurs without known family predisposition, as the underlying mutation can arise anew.
The Retinoblastoma Gene on Chromosome 13
It is important to note that regardless of whether retinoblastoma is hereditary or non-hereditary, the mutation occurs in the retinoblastoma gene on chromosome 13. Since each chromosome is present twice in every cell, there are also two retinoblastoma genes. A tumor can only develop if both genes are mutated.
Symptoms of Eye Cancer
The “Cat’s Eye”
The most noticeable warning sign is a white pupil in flash photos. If the pupil appears white under certain lighting conditions, such as when photographing, instead of the usual reddish reflex, this can be an indication of the disease. This phenomenon is also known as “cat’s eye” (medically called leukocoria). However, white pupils are not visible in all images. Additionally, a white pupil does not necessarily indicate retinoblastoma. Other, often harmless causes or photographic effects can also be responsible. Therefore, it is important to have this medically evaluated to rule out a serious condition.
Red Pupil
Another signal is photos where one pupil appears black (or another color) while the other appears red.
Strabismus
Strabismus can also be a symptom of eye cancer. Especially in young children, this should be medically evaluated to identify possible causes early.
Persistent Redness or Swelling of the Eye
If a child’s eye is repeatedly inflamed, red, or swollen—and without an existing infection—this could also be a sign of a disease.
Changes in Iris Color
If the iris shows color changes, it is important to have this medically checked as well.
Deterioration of Vision
Vision impairment (“eye tremor”) or loss of visual acuity could also be signs of a tumor. The same applies if a child does not focus properly with their eyes or reacts differently to visual stimuli compared to peers.4
Diagnosis of the Disease
If a doctor finds indications of eye cancer during a medical history, ophthalmological, or physical examination, the patient must be immediately referred to a specialized clinic. Various examinations must then determine which form of the disease (hereditary or non-hereditary) is present, the stage of the disease, and the extent of its spread in the patient.
Ophthalmoscopy
One of the most important methods for detecting retinoblastoma is ophthalmoscopy. Using a special ophthalmoscope and a strong light source, the back of both eyes is observed. If a tumor is present, it can also be determined how far it has spread. This is particularly important for classifying the different stages of the disease. Factors such as the size and location of the tumors, number, and spread to other organs must also be considered.
Imaging Techniques
To precisely determine tumor spread, imaging techniques such as ultrasound examination (sonography) and magnetic resonance imaging (MRI) are used. The former allows for tumor measurement, while an MRI can reveal whether the tumor is confined to one or both eyes.
Additional Examinations
Especially in rare cases—when the disease is already advanced, or chemotherapy is planned—additional diagnostic procedures may be used:
- Bone scintigraphy to assess possible bone involvement
- Chest X-ray examination
- Bone marrow aspiration to examine the bone marrow
- Lumbar puncture to analyze cerebrospinal fluid
Genetic Diagnostics
Aside from imaging techniques, it can also be determined whether the disease is hereditary or non-hereditary. As part of the initial diagnosis, human genetic counseling is offered. After the parents of the child have consented, a molecular genetic analysis of the blood (genetic test) can be conducted. This involves examining the DNA for mutations in the retinoblastoma gene.
If a mutation is detected, hereditary retinoblastoma is present. In this context, the parents and siblings of the affected child must also be examined. This allows for risk assessment and planning of appropriate preventive and control measures within the family.5
He was just a few weeks old when he was diagnosed with eye cancer.
Symptoms That May Indicate Vaginal Cancer
Therapy Planning
Once the diagnosis is made, therapy planning follows. To enable individualized and risk-adapted treatment, various risk or prognostic factors must be considered. A crucial criterion and an important prognostic factor is the extent of tumor spread at the time of diagnosis.
Tumor Staging
Eye cancer is classified based on its spread. It must first be distinguished whether the tumor affects only the eye (intraocular retinoblastoma) or has already spread to surrounding tissue (extraocular retinoblastoma). The extent of the tumor is assessed separately for each eye.
Classification Systems
There are various classification systems for intraocular and extraocular retinoblastoma:
Intraocular Retinoblastoma
The “International Classification of Retinoblastoma” (ICRB, Philadelphia version) is most commonly used. This classification system evaluates the location in the eye, tumor size, and the presence and extent of vitreous seeding. Based on this, five disease stages (A to E) are distinguished. Vitreous seeding refers to the infiltration of tumor cells into the vitreous body of the eye, the space between the lens and retina. Tumor cells can detach from the retina and enter the vitreous body, complicating treatment as they spread within the eye. Common therapies like laser or local radiation are less effective.
Extraocular Retinoblastoma
In this case, staging is done according to the “International Retinoblastoma Staging System” (IRSS). The system divides the disease into several stages following surgical tumor removal (enucleation). It also considers whether the tumor has affected the sclera and optic nerve or if metastases have formed in other organs. If no eye is removed, it is generally referred to as conservatively treated retinoblastoma (Stage 0).
Treatment
Treatment of eye cancer must be tailored to each child. Generally, the following options are available:
Surgical Removal of the Eye
If only one eye is affected and vision is severely impaired or already lost, the entire eyeball, along with part of the optic nerve, must be removed. If both eyes are affected, the priority is to preserve vision at least partially and treat the cancer without removing both eyes. In some cases, the more severely affected eye may be removed.
Alternative Treatment Methods
Aside from surgery, there are various therapeutic procedures:
- Radiation therapy: For very small tumors, “brachytherapy” (radiation with a radioactive patch) may be used.
- Laser therapy & cryotherapy: Small tumors are destroyed by targeted heat (laser) or cold (cryotherapy).
- Intra-arterial chemotherapy: The medication is administered directly through the main artery supplying blood to the eye.
Use of Chemotherapy
Chemotherapy is often used in combination with other procedures—mainly because it rarely cures retinoblastoma alone. However, the therapy can help shrink larger tumors or treat cancer that has already spread outside the eye. Various medications are used, either in tablet form or intravenously.
Risks of Radiation Therapy
However, radiation of the eye is associated with serious side effects, such as:
- Cataracts (gray star)
- Chronic dry eye
- Vision deterioration
- Growth disorders of facial bones, which can lead to deformation in the worst case
- Tissue atrophy in the eye area
- Increased risk of a second cancer in the irradiated area
To detect possible recurrence of the tumor or the development of a second cancer early, it is important for the child to be monitored and examined.
Prognosis of the Disease
Due to continuous advancements in therapy, diagnostics, and early detection, the prognosis for retinoblastoma patients in Western countries has significantly improved. With early diagnosis and treatment, more than 97 percent of affected children survive today.6