title: Decreased retinal nerve fiber layer thickness in patients with obstructive sleep apnea syndrome: A meta-analysis.
abstract: OBJECTIVE
  To investigate the changes of retinal nerve fiber layer (RNFL) thickness in obstructive sleep apnea syndrome (OSAS) patients.
  
  
  METHODS
  Relevant studies were selected from 3 major literature databases (PubMed, Cochrane Library, and EMBASE) without language restriction. Main inclusion criteria is that a case-control study in which RNFL thickness was measured by a commercial available optical coherence tomography (OCT) in OSAS patients. Meta-analysis was performed using STATA 12.0 software. Efficacy estimates were evaluated by weighted mean difference with corresponding 95% confidence intervals (CIs). Primary outcome evaluations were: the average changes of RNFL thickness in total OSAS patients, subgroup analysis of RNFL thickness changes in patients of different OSAS stages, and subgroup analysis of 4-quadrant RNFL thickness changes in total OSAS patients.
  
  
  RESULTS
  Of the initial 327 literatures, 8 case-control studies with 763 eyes of OSA patients and 474 eyes of healthy controls were included (NOS scores ≥6). For the people of total OSAS, there had an average 2.92 μm decreased RNFL thickness compared with controls (95% CI: -4.61 to -1.24, P = 0.001). For subgroup analysis of OSAS in different stages, the average changes of RNFL thickness in mild, moderate, severe, and moderate to severe OSAS were 2.05 (95% CI: -4.40 to 0.30, P = 0.088), 2.32 (95% CI: -5.04 to 0.40, P = 0.094), 4.21 (95% CI: -8.36 to -0.06, P = 0.047), and 4.02 (95% CI: -7.65 to -0.40, P = 0.03), respectively. For subgroup analysis of 4-quadrant, the average changes of RNFL thickness in Superior, Nasal, Inferior, and Temporal quadrant were 2.43 (95% CI: -4.28 to -0.57, P = 0.01), 1.41 (95% CI: -3.33 to 0.51, P = 0.151), 3.75 (95% CI: -6.92 to -0.59, P = 0.02), and 0.98 (95% CI: -2.49 to 0.53, P = 0.203), respectively.
  
  
  CONCLUSIONS
  Our study suggests that RNFL thickness in OSAS patients is much thinner than healthy population, especially in superior and inferior quadrant. The impact of OSAS disease on RNFL and visual function should be taken seriously in the further study.
authors: Department of Ophthalmology, The Fifth Affiliated Hospital of Zhengzhou University Department of Ophthalmology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
authors: Cheng-Lin
authors: CL
authors: Sun
authors: Li-Xiao
authors: LX
authors: Zhou
authors: Yalong
authors: Y
authors: Dang
authors: Yin-Ping
authors: YP
authors: Huo
authors: Lei
authors: L
authors: Shi
authors: Yong-Jie
authors: YJ
authors: Chang
mesh_terms: D016022:Case-Control Studies; D006801:Humans; D008875:Middle Aged; D055351:Retinal Neurons / Q000473:pathology*; D020181:Sleep Apnea, Obstructive / Q000473:pathology*; D041623:Tomography, Optical Coherence