4 Prevention and treatment
For patients under taxane administration, it is recommended to have a baseline examination of ophthalmology before treatment, such as visual acuity, intraocular pressure, fundus, color vision, visual field examination, and etc. and to closely observe whether there are new ocular symptoms during the treatment process. Patients with ocular symptoms in the course of medication should be referred to have ocular consultancy and have a complete ocular checkup in time. For the ocular surface diseases caused by paclitaxel drugs, such as dry eye, conjunctivitis, keratitis, and etc. Usually, we recommend to use artificial tears, non-steroidal anti-inflammatory drugs, antibiotic eye ointment and other symptomatic treatment. Lacrimal duct obstruction or narrow, tear overflow can be used lacrimal duct irrigation or lacrimal duct exploration [19]. The adverse side effects occur on the ocular surface caused by paclitaxel are reversible and can be recovered after withdrawal and symptomatic treatment, with within several days to 5 months [19].
For patients with macular edema and impaired vision, there are no authentic treatment guidelines. The main treatment strategy is to stop chemotherapy, but this option should be mainly determined by the systemic status. Some scholars have tried to use carbonic anhydrase inhibitors, glucocorticoids and anti-vascular endothelial growth factor drugs for treatment. Ehlers et al. [29] showed that topical use of 2% carbonic anhydrase inhibitors could effectively remission paclitaxel-associated macular edema and improve visual acuity after the cessation of chemotherapy, suggesting that carbonic anhydrase inhibitors might be used as an early treatment option. Glucocorticoids are also being considered. In cases that dexamethasone was injected intravitreally, the retinal thickness of the patient decreased after 1 month, but the macular edema persisted and the presence of macular edema disappeared significantly after 2 months of discontinuation of chemotherapy [30]. The similar finding was also observed in cases subjected to sub-Tenon injections of triamcinolone acetonide, suggesting that glucocorticoids may merely relieve rather than resolve the problem [31]. Anti-vascular endothelial growth factor drugs, a widely adopted drug in treating diabetic macular edema, seemed has little effect to paclitaxel-induced macular edema. In Rahman’s study, continuous binocular intravitreal bevacizumab resulted in stable vision but persistent macular edema [32], which reveals the different mechanisms of taxanes induced macular edema from diabetic macular edema and retinal vein occlusion-macular edema. In addition, some researchers have found that carvone protects against paclitaxel-induced retinal and optic nerve cytotoxicity in rats[33], while further studies remain to be carried out.