Retinoblastoma is a rare type of eye cancer that primarily affects young children, usually under the age of five. It develops in the retina, the light-sensitive tissue at the back of the eye, and can cause vision loss or even be life-threatening if not treated promptly. Early signs include a white glow in the pupil, eye redness, or misaligned eyes. Prompt diagnosis and treatment, which may include chemotherapy, radiation, or surgery, are crucial for preserving vision and preventing the spread of cancer.