6. Retinoblastoma
Retinoblastoma is a cancer that initially develops in the retina, the nerve tissue that lines the back of the eye. Often it occurs in only one of the eyes. However, in more rare cases it can affect both of the eyes. Unfortunately, retinoblastoma tends to spread to other parts of the body including the lymph nodes and the bone marrow. However, this type of cancer has a very high survival rate. Because it targets such a crucial part of the body, the eyes, the main goal of the treatment of retinoblastoma is to ensure that eyesight is not impaired. Things to look out for include a pupil that is enlarged in one eye, different coloured irises and crossed eyes.