title: Retinal nerve fiber layer thickness changes in obstructive sleep apnea syndrome: a systematic review and Meta-analysis.
abstract: OBJECTIVE
  To evaluate the retinal nerve fiber layer (RNFL) thickness changes in patients with obstructive sleep apnoea syndrome (OSAS), and detect possible prevalence of glaucoma in this population.
  
  
  METHODS
  Comprehensive studies were conducted on the Cochrane Library, PubMed and Embase through March, 2015. Only studies that fit the selection criteria about RNFL and OSAS would be included. For the measures, we calculated the 95% confidence interval (CI) and weighted mean differences (WMD). The systematic review and Meta-analysis was performed by RevMan 5.2 software.
  
  
  RESULTS
  Nine case-control studies were analyzed containing a total of 1086 cases and 580 controls. Average RNFL thickness in OSAS was reduced significantly compared with healthy controls in random effects model (WMD=-2.56, 95% CI: -4.82 to -0.31,P=0.003,I2=57%). A significant RNFL thickness reduction were found between the two groups in inferior quadrant (WMD=-3.11, 95% CI: -5.53 to -0.69,P=0.01), superior quadrant (WMD=-2.37, 95%CI: -4.7 to 0.04,P=0.05). In nasal quadrant (WMD=-2.54, 95% CI: -6.53 to 1.45,P=0.21) and temporal quadrant (WMD=-1.26, 95% CI: -2.19 to 0.47,P=0.15) there was no difference of RNFL thickness between the two groups.
  
  
  CONCLUSIONS
  The results show that RNFL thickness is lower in patients with moderate or severe OSAS than in normal subjects or patients with mild OSAS according to the nine homogeneity studies.
authors.affiliation: Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei Province, China.
authors.forename: Jia-Song
authors.initials: JS
authors.lastname: Wang
authors.affiliation: Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei Province, China.
authors.forename: Hua-Tao
authors.initials: HT
authors.lastname: Xie
authors.affiliation: Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei Province, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Jia
authors.affiliation: Department of Ophthalmology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, Hubei Province, China.
authors.forename: Ming-Chang
authors.initials: MC
authors.lastname: Zhang
keywords: Meta-analysis; obstructive sleep apnea syndrome; retinal nerve fiber layer thickness