Inclusion Criteria:  The patient's guardian signs an informed consent form and is willing to receive follow-up according to the schedule of the trial; Children of more than 3 months and under 5 years of age who have not received any anti-cancer treatment;  The target eye must meet the following requirements:  Clinically diagnosed as monocular retinoblastoma; According to the IIRC diagnostic criteria, the treatment eye is classified as Group E stage without clinical high-risk factors (Table 1); No refractive medium turbidity and/or pupillary abnormalities that affect the fundus examination; IOP≤21mmHg.  Sufficient organ function at baseline.  Exclusion Criteria:  Subjects with any of the following eye conditions:  Patients diagnosed as stage E retinoblastoma in one eye, but with high-risk factors: neovascular glaucoma; refractive interstitial opacity caused by anterior chamber, vitreous or subretinal hemorrhage; tumor invasion of optic nerve posterior to the cribriform plate and choroid (range of diameter> 2 mm), sclera, and anterior chamber; Treatment-naïve pediatric patients;  Patients with any of the following systemic diseases:  With a history of allergies or have allergic reactions to fluorescein sodium, with a history of allergies to protein products for treatment or diagnosis, and have allergic reactions to two or more drugs and/or non-drug factors, or suffering from allergic diseases; Low birth weight children, and severely growth-stunted children; Children who need systemic treatment for other system diseases; Any condition that should be excluded from the study in the opinion of the investigator.