Effect and Mechanisms of Medicinal Plants on Dry Eye Disease: A Systematic Review

Introduction: Dry Eye Disease (DED) is one of the most common problems and reasons for referring to ophthalmology clinics, which has been exacerbated by the increased use of computers and mobile phones. Aim: The purpose of the present systemic review was to review the effects and mechanism of medicinal plants in DED treatment. Materials and Methods: The key words "Dry eye" or "Keratoconjunctivitis sicca" or "keratitis sicca" in combination with "medicinal plant", "herb", and "phyto" were used to conduct the review. Clinical and experimental published articles in English language between 2000-2018 were retrieved from databases including the Institute for Scientific Information (ISI), PubMed and Scopus. Results: Totally, 199 articles were retrieved from the electronic database and finally 17 articles were included in the final analysis. Various plants such as Buddleja officinalis, Aristotelia chilensis, Prunus armeniaca, Hippophae rhamnoides, Lycium barbarum, and Rhynchosia volubilis Lour are effective in treating DED through different mechanisms. Herbal derivatives such as curcumin, antioxidant glasses, phytoestrogen, ferulic acid, and kaempferol can be used as food supplement independently and in some cases along with chemical drugs. Chinese herbal formulations and compounds such as 'Chi-Ju-Di-Huang-Wan', 'TriphalaGhritaNetratarpan', and 'ShengJinRunZaoYangXue' granules can play a role in inducing anti-oxidant and anti-inflammatory properties in the treatment of the disease. Conclusion: Generally, medicinal plants reduce tear film stability by decreasing osmolarity and increasing tear production. Several mechanisms, including the reduction of Reactive Oxygen Species (ROS) (antioxidant activity), the prevention of cell apoptosis, the modulation of inflammatory factors, and the regulation of androgens, can affect lacrimal glands and membrane cells, thereby helping to treat DED.