The primary objective of the study is to evaluate the effect of intravenously infused nitroglycerin on the incidence of the cardio-respiratory side effects during the intra-arterial chemotherapy for retinoblastoma in pediatric patients. The intra-arterial chemotherapy at the ophthalmic artery is an important treatment option for retinoblastoma. However, the cardio-respiratory side effects (sudden onset of bradycardia, hypotension, a severe decrease in the compliance of lung, hypoxia) occasionally occurs during catheter manipulation in the ophthalmic artery. One of the purported mechanisms of cardio-respiratory side effects is vagal activation from the activation of trigeminal ganglion by afferent signals from the ophthalmic artery. Additionally, the chemotherapy agent can cause intra-arterial retinal precipitates. Therefore, it is expected that the dilation of the retinal artery may reduce the cardio-respiratory side effects and intra-arterial retinal precipitates. The hypothesis of this study is that the intravenously infused nitroglycerin will increase the compliance of the ophthalmic and retinal artery and decrease vagal stimulation and cardio-respiratory side effects during catheter manipulation and chemotherapy agent infusion. This is a single-center, double-blind, randomized, placebo-controlled study comparing the effect of intravenously infused nitroglycerin and saline on the incidence of the cardio-respiratory side effect in pediatric retinoblastoma patients undergoing intra-arterial chemotherapy. Prior to the procedure, each patient will be randomized into either the control-first arm, saline, or study-first arm, nitroglycerin.