title: Efficacy of nutritional supplementation with omega-3 and omega-6 fatty acids in dry eye syndrome: a systematic review of randomized clinical trials.
abstract: OBJECTIVE
  To critically appraise scientific evidence regarding the efficacy of nutritional supplementation with omega-3 and omega-6 fatty acids for the treatment of dry eye syndrome (DES).
  
  
  METHODS
  A systematic review of randomized clinical trials was performed. Two independent reviewers selected and analysed the scientific papers that met inclusion and exclusion criteria. Objective and subjective efficacy outcomes were assessed.
  
  
  RESULTS
  The trials involved a total of 2591 patients in fifteen independent studies. All studies were published between 2005 and 2015. The supplements used were mostly omega-3 and omega-6 in different proportions. Subjective improvement was measured using mainly Ocular Surface Disease Index (OSDI) test and Dry Eye Severity Score (DESS) test: significant differences in favour of the experimental group were found in seven of the studies. The objective amelioration was assessed by lacrimal function parameters: Tear break-up time (TBUT) significantly increased in nine studies and Schirmer's test in four studies.
  
  
  CONCLUSIONS
  We observed a discrete improvement in the parameters of tear function. Scientific evidence is not strong enough to systematically recommend the use of omega-3 and omega-6 fatty acids as a standalone treatment of DES independently from its aetiology. However, they could be considered as an effective alternative to topical treatment in patients with DES secondary to certain pathologies.
authors.affiliation: Department of Ophthalmology, Granada Hospital Complex, Granada, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Molina-Leyva
authors.affiliation: Department of Preventive Medicine and Public Health, Universidad de Granada, Granada, Spain.|Department of Dermatology, Torrecárdenas Hospital Complex, Almería, Spain.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Molina-Leyva
authors.affiliation: Department of Preventive Medicine and Public Health, Universidad de Granada, Granada, Spain.
authors.forename: Aurora
authors.initials: A
authors.lastname: Bueno-Cavanillas
mesh_terms: D019587:Dietary Supplements; D015352:Dry Eye Syndromes / Q000178:diet therapy*; D015525:Fatty Acids, Omega-3 / Q000627:therapeutic use*; D043371:Fatty Acids, Omega-6 / Q000627:therapeutic use*; D006801:Humans; D016032:Randomized Controlled Trials as Topic; D016896:Treatment Outcome
chemical_list: D015525:Fatty Acids, Omega-3; D043371:Fatty Acids, Omega-6
keywords: clinical trials; dry eye; omega fatty acids; oral supplementation; systematic review