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].