The causes of most forms of eye cancer are not well understood. Continuing research has shown the role of genes in many forms of cancer. For example, retinoblastoma is caused by a genetic mutation, which is either passed on from a child’s parents or occurs during embryonic development. The uncertainty about causes for other forms of eye cancer makes it more difficult to identify risk factors for the condition. However, certain risk factors are associated with each type of eye cancer. These include:

• Race/ethnicity. Intraocular melanoma is more common in light-skinned people than dark-skinned people.
  
  
• Eye coloration. People with blue irises have an increased risk of developing primary intraocular melanoma.
  
  
• Heredity. Several inherited conditions are related to an increased risk for eye cancers. About 40 percent of retinoblastomas are inherited, according to the American Cancer Society. In addition, the presence of certain conditions can increase the likelihood of intraocular melanoma. A condition called dysplastic nevus syndrome, which causes abnormal skin moles, can increase an individual’s risk of developing eye melanoma. Melanomas of the eye can also run in some families with no history of dysplastic nevus syndrome or oculodermal melanocytosis.
  
  
• Weakened immune system. Having a compromised immune system is a risk factor of developing primary lymphoma of the eye. Therefore, individuals with weakened immune systems, such as people with AIDS or the elderly are more likely to develop eye lymphoma than individuals with healthy immune function.
  
  
• Age. Nearly two-thirds of patients diagnosed with retinoblastoma are under 2 years of age, and 95 percent of retinoblastoma patients are younger than 5. This condition is extremely rare in adults. Age is also considered a risk factor for the development of eye lymphoma, which is more common in elderly people.
  
  
• Exposure to sun. Excessive exposure to sunlight may be a risk factor for eye melanoma. However, this has not yet been proven.
  
  
• Welding. Some evidence indicates that long-term exposure to equipment used in welding increases an individual’s risk of developing eye melanoma. However, this evidence is not conclusive, and further study is needed.