Here, we evaluate the feasibility of cell-free RNA (cfRNA)- and circulating tumor cell RNA (ctcRNA)-based liquid biopsy for the sensitive detection of disseminated retinoblastoma using digital PCR (dPCR) targeting the retina-specific markers <i>CRX</i> and <i>RBP3</i>. The gene discussed is RBP3; the disease is neoplasm.