title: Lutein and zeaxanthin supplementation and association with visual function in age-related macular degeneration.
abstract: OBJECTIVE
  To evaluate the effects of lutein and zeaxanthin on visual function in randomized controlled trials (RCTs) of AMD patients.
  
  
  METHODS
  Relevant studies were identified by searches on PubMed, EMBASE, Web of Science, and Cochrane Library database up to April 2014. Three investigators independently determined the eligibility of RCTs, which compared lutein and zeaxanthin intervention with placebo. The adjusted weighted mean differences (WMDs) from each study were extracted to calculate a pooled estimate with its corresponding 95% confidence interval (CI). The main outcome measurements included visual acuity (VA), contrast sensitivity (CS), glare recovery time (GRT), and subjective perception of visual quality.
  
  
  RESULTS
  Eight RCTs involving 1176 AMD patients were included in the meta-analysis. Xanthophyll carotenoids supplementation was associated with significant decrease in logMAR levels compared with the placebo group (WMD, -0.04; 95% CI, -0.06 to -0.03), and during intervention, each 1-mg/day increase in these carotenoids supplementation was related to a 0.003 reduction in logMAR level of VA. Remarkable benefit was also observed at all four spatial frequencies of CS (WMD ranging from 0.08-0.18; all P < 0.05) in contrast to placebo. Furthermore, association was observed between the postintervention increase in macular pigment optical density and improvements in VA (r = -0.58; P = 0.02), and in CS at 12 cycles/degree as well (r = 0.94; P < 0.001).
  
  
  CONCLUSIONS
  Lutein and zeaxanthin supplementation is a safe strategy for improving visual performance of AMD patients, which mainly showed in a dose-response relationship.
authors.affiliation: School of Public Health, Xi'an Jiaotong University Health Science Center, Xi'an, China.
authors.forename: Rong
authors.initials: R
authors.lastname: Liu
authors.affiliation: School of Public Health, Xi'an Jiaotong University Health Science Center, Xi'an, China.
authors.forename: Tian
authors.initials: T
authors.lastname: Wang
authors.affiliation: School of Public Health, Xi'an Jiaotong University Health Science Center, Xi'an, China.
authors.forename: Bao
authors.initials: B
authors.lastname: Zhang
authors.affiliation: The First Affiliated Hospital, Xi'an Jiaotong University College of Medicine, Xi'an, China.
authors.forename: Li
authors.initials: L
authors.lastname: Qin
authors.affiliation: The First Affiliated Hospital, Xi'an Jiaotong University College of Medicine, Xi'an, China.
authors.forename: Changrui
authors.initials: C
authors.lastname: Wu
authors.affiliation: School of Public Health, Xi'an Jiaotong University Health Science Center, Xi'an, China.
authors.forename: Qingshan
authors.initials: Q
authors.lastname: Li
authors.affiliation: School of Public Health, Xi'an Jiaotong University Health Science Center, Xi'an, China.
authors.forename: Le
authors.initials: L
authors.lastname: Ma
mesh_terms: D019587:Dietary Supplements; D006801:Humans; D014975:Lutein / Q000008:administration & dosage*; D008268:Macular Degeneration / Q000503:physiopathology / Q000517:prevention & control*; D014792:Visual Acuity / Q000187:drug effects / Q000502:physiology*; D065146:Zeaxanthins / Q000008:administration & dosage*
chemical_list: D065146:Zeaxanthins; D014975:Lutein
keywords: age-related macular degeneration; lutein; meta-analysis; visual function; zeaxanthin