Retinoblastoma is the most common pediatric malignant intraocular tumour and originates from the retina. Treatment of eyes with advanced intraocular retinoblastoma remains a challenge. The historic standard of care for patients with unilateral disease is enucleation and for those with bilateral disease, a variety of modalities have been tried. These include radiation therapy, systemic chemotherapy, periocular administration of chemotherapy, selective intra-arterial chemotherapy, and intravitreal chemotherapy. Unfortunately, all of these modalities are associated with significant morbidity and investigators are looking for new ways to treat these patients either with novel directed drug delivery methods or with new less toxic agents. This study will evaluate the safety and efficacy of topotecan delivered directly to the eye using a novel sustained-release topotecan episcleral plaque (also referred to as a Chemoplaque) in patients with active residual or recurrent intraocular retinoblastoma in at least one eye following completion of first-line therapy. The study intervention involves the insertion and removal of the Chemoplaque, examinations under anaesthesia (EUAs), visits to clinic to monitor for adverse events throughout, and post plaque removal toxicity evaluation. EUAs, clinic visits and laboratory tests are standard of care for retinoblastoma patients.