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External beam radiation has been used since the early 1900's as a way to save the eye(s) and vision. Retinoblastoma is sensitive to radiation, and frequently the treatment is successful. The radiation treatment is performed on an outpatient basis five times per week over a 3 to 4 week stretch. Custom-made plaster-of paris molds are made to prevent the head from moving during treatment and sometimes sedatives (medicines which help relax the children) are prescribed prior to treatment.

Tumors usually get smaller (regress) and look scarred after external beam radiation treatment but they rarely disappear completely. In fact, they may even become more obvious to the parent as they shrink, because the pinkish-grey tumor mass is replaced by white calcium. Immediately after treatment, the skin may be sunburned or a small patch of hair may be lost in the back of the head from the beam exit position. Following external beam radiation, long-term effects can include cataracts, radiation retinopathy (bleeding and exudates of the retina), impaired vision, and temporal bone suppression (bones on the side of the head which do not grow normally). Radiation can also increase a child's risk of developing other tumors outside the eye for those children who carry the abnormal gene in every cell of their bodies.

Radioactive plaques are disks of radioactive material that were developed in the 1930's to radiate retinoblastoma. Today, the isotope iodine-125 is used and the plaques are custom-built for each child. According to New York State radiation safety rules, the child must be hospitalized for this procedure, and undergoes two separate operations (one to insert the plaque and one to remove it) over 3 to 7 days. No pregnant visitors or health care professionals may visit or care for the child, and children under twelve years old are not permitted to visit. Patients take eye drops following plaque surgery for 3 to 4 weeks to prevent infection and inflammation. Following the plaque, long-term effects including cataracts, radiation retinopathy, and impaired vision may occur.

Laser therapy, sometimes called photocoagulation or laser hyperthermia (which are two different techniques), is a non-invasive treatment for retinoblastoma. Lasers vey effectively destroy smaller retinoblastoma tumors. This type of treatment is usually done by focusing light through the pupil onto and surrounding the cancers in the eye. Recently a new delivery system of the laser, called a diopexy probe, has enabled treatment of the cancer by aiming the light through the wall of the eye and not through the pupil. Laser treatment is done under local or general anesthesia, usually does not have any post-operative pain associated with it, and does not require any post-operative medications. Laser can be used alone or in addition to external-beam radiation, plaques, or cryotherapy.

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