Ocular dysmotility after intra-arterial chemotherapy for retinoblastoma

We report the case of a 15-month-old boy with retinoblastoma who developed exotropia secondary to a right medial rectus infarct after intra-arterial chemotherapy. He had unilateral sporadic group C tumor (International Classification of Retinoblastoma) and was treated with intra-arterial melphalan. One week after the first session of intra-ophthalmic arterial melphalan chemotherapy, he was noted to have orbital congestion, exotropia, and right adduction limitation. Magnetic resonance imaging was suggestive of a right medial rectus infarct. The tumor showed a good response to intra-arterial chemotherapy but the exotropia persisted.