Vincristine sulfate (Oncovin) is a commonly used drug in the treatment of acute leukemia and other malignancies. This paper lists a series of 20 patients with ptosis, other ocular muscle paresis, and fifth and seventh nerve involvement which appeared to have been induced by vincristine. Most showed signs of peripheral neuropathy, other cranial nerve palsies, nausea and vomiting, constipation, or alopecia as well. Toxic reactions usually improved following decreased dosage or discontinuation of drug therapy.
Albert DM, Wong VG, Henderson ES. Ocular Complications of Vincristine Therapy. Arch Ophthalmol. 1967;78(6):709-713. doi:10.1001/archopht.1967.00980030711004