Nutrition and dry eye: a systematic review.

OBJECTIVE: To identify the clinical evidence in the literature about the relationship between nutrition or dietary supplements and dry eye syndrome. METHODS: A systematic review was performed after selecting descriptors (DECS and MeSH) using electronic database (Pubmed, Cochrane, and Embase) for the words 'diet', 'food', 'nutrition' and 'dry eye syndrome' appearing in the title, abstract or key words. Papers published in any language during the last 10 years were selected. A scoring system regarding the scientific evidence (GRADE) was applied for all chosen manuscripts. RESULTS: Only 17 papers were considered as relevant for our review taking into account our search criteria. The main features of the studies published have been summarized in two tables. CONCLUSION: The use of omega-3 polyunsaturated fatty acids, taken in the diet or as dietary supplements, appears as the most analyzed element. Omega-3 provides the greatest degree of scientific evidence regarding its usefulness as a coadjuvant in the management of dry eye. It can be said that moderate scientific evidence supports its use as a helpful tool in the treatment of dry eye syndrome. However, it is not possible to define the exact dosage to achieve a clinical benefit.