For the longest time I thought RB could only affect children. Well, I have proven myself wrong. It says that even though it is VERY rare, adult Retinoblastoma IS possible. The conclusion of the report is copied directly from the source and pasted below.
Retinoblastoma occurring in adults is a rare finding.
In most large series of retinoblastomas, no adults are included. Only eight patients 20 years of age or older with retinoblastomas have been documented previously. In the current case, the patient had no evidence of orbital recurrence or metastasis 6 years after enucleation of the eye. It may be important for clinicians to consider this diagnosis when confronted with a retinal mass of unknown etiology in adults. I state here, on my page, that I'm not a doctor.