3.4 Optic nerve injury
Hofstra et al. [24] mentioned a case of ovarian cancer patients received 6 times of paclitaxel intraperitoneal chemotherapy after sudden blindness, does not appear to have a headache, nausea, or other central nervous system symptoms. Eye examination showed his eyes left hemianopsia, prompt visual cortex damage. Ease withdrawal symptoms after 10 d, diagnosis of vasospasm caused by optic nerve function defect. It may be related to intraperitoneal chemotherapy with paclitaxel. When paclitaxel was infused, patient experienced scotomata small luminous dotsor ”flies” in the visual fields of both eyes, lasted a few minutes to several hours. It was speculated that paclitaxel may damage the optic nerve [25]. Sediman et al. [6, 23] estimated that among 25 breast cancer patients who received paclitaxel 250-275 mg/m2 chemotherapy for the first time, 6 of them saw the flashing of stars or fireworks in the whole field of vision 3 h after the chemotherapy which usually last 15 min to 3 h. There were no significant chronic sequelae. And this phenomenon occurred again when the same or slightly lower dose of chemotherapy (less than 275 mg/m2 but not less than 250 mg/m2) was received, but wouldn’t appear when the dose was less than 250 mg/m2. It was considered to be a transient optic nerve vasogenic reaction induced by paclitaxel, dose-dependent and reversible. In addition, docetaxel treatment resulted in visual loss, intraocular pressure, enlargement of the optic cup, and loss of bilateral visual field [5, 26]. There are studies that evaluated visual electrophysiology in 14 breast cancer patients undergoing paclitaxel chemotherapy. ERG b-wave latency significantly increased. Seven patients showed abnormal ERG, oscillating potentials, 30 Hz flashing light response and visual evoked potentials (VEP) monitoring in different combinations, twelve patients presented with transient dark spots and blurred vision with abnormal oscillating potentials. It suggested that the most likely mechanism of visual symptoms and electrophysiological changes during paclitaxel administration is vascular dysregulation in the retina, or ischemic mechanisms when the optic nerve is involved [27]. In a study of 47 patients who received paclitaxel for non-small lung cancer, three of them showed abnormal VEP, showing a significant decrease in P100 amplitude and a slight increase in latency. The abnormal increase in P100 latency of VEP is considered to be typical demyelinating optic neuropathy [28].