title: Peripapillary retinal nerve fiber layer changes in preclinical diabetic retinopathy: a meta-analysis.
abstract: BACKGROUND
  Diabetic retinopathy is a microvascular neurodegenerative disorder in diabetic patients. Peripapillary retinal nerve fiber layer changes have been described in patients with preclinical diabetic retinopathy, but study results have been inconsistent.
  
  
  OBJECTIVE
  To assess changes in peripapillary retinal nerve fiber layer thickness in diabetic patients with preclinical diabetic retinopathy.
  
  
  METHODS
  A literature search was conducted through PubMed, EMBASE, Web of Science and Cochrane Library. Case-control studies on RNFL thickness in preclinical diabetic retinopathy patients and healthy controls were retrieved. A meta-analysis of weighted mean difference and a sensitivity analysis were performed using RevMan 5.2 software.
  
  
  RESULTS
  Thirteen case-control studies containing 668 diabetic patients and 556 healthy controls were selected. Peripapillary RNFL thickness was significantly reduced in patients with preclinical diabetic retinopathy compared to healthy controls in studies applying Optical Coherence Tomography (-2.88 μm, 95%CI: -4.44 to -1.32, P = 0.0003) and in studies applying Scanning Laser Polarimeter (-4.21 μm, 95%CI: -6.45 to -1.97, P = 0.0002). Reduction of RNFL thickness was significant in the superior quadrant (-3.79 μm, 95%CI: -7.08 to -0.50, P = 0.02), the inferior quadrant (-2.99 μm, 95%CI: -5.44 to -0.54, P = 0.02) and the nasal quadrant (-2.88 μm, 95%CI: -4.93 to -0.82, P = 0.006), but was not significant in the temporal quadrant (-1.22 μm, 95%CI: -3.21 to 0.76, P = 0.23), in diabetic patients.
  
  
  CONCLUSIONS
  Peripapillary RNFL thickness was significantly decreased in preclinical diabetic retinopathy patients compared to healthy control. Neurodegenerative changes due to preclinical diabetic retinopathy need more attention.
authors.affiliation: Department of Ophthalmology, Chinese PLA General Hospital, Beijing, China.
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Ophthalmology, Chinese PLA General Hospital, Beijing, China.
authors.forename: Chuang
authors.initials: C
authors.lastname: Nie
authors.affiliation: Department of Ophthalmology, Chinese PLA General Hospital, Beijing, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Gong
authors.affiliation: Department of Ophthalmology, Chinese PLA General Hospital, Beijing, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Ophthalmology, Chinese PLA General Hospital, Beijing, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Jin
authors.affiliation: Department of Ophthalmology, Chinese PLA General Hospital, Beijing, China.
authors.forename: Shihui
authors.initials: S
authors.lastname: Wei
authors.affiliation: Department of Ophthalmology, Chinese PLA General Hospital, Beijing, China.
authors.forename: Maonian
authors.initials: M
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D003930:Diabetic Retinopathy / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D012160:Retina / Q000473:pathology*; D041623:Tomography, Optical Coherence; D055815:Young Adult