title: Choroidal thickness and primary open-angle glaucoma: a cross-sectional study and meta-analysis.
abstract: OBJECTIVE
  The purpose of this study was to examine the choroidal thickness of patients with POAG using enhanced depth imaging optical coherence tomography (EDI-OCT) and compare them with healthy subjects. We first conducted a cross-sectional study and then performed a meta-analysis to address this issue further.
  
  
  METHODS
  Enhanced depth imaging optical coherence tomography was used to measure the macular choroidal thickness of the POAG and healthy eyes. Univariate and multivariate linear regression analyses were performed to assess the association between choroidal thickness and clinical factors. The meta-analysis was managed with Stata 12.0 software.
  
  
  RESULTS
  Seventy-six healthy and 52 POAG subjects were recruited for this study. Age and axial length were the significant factors associated with subfoveal choroidal thickness in each group. There were no significant differences in choroidal thickness at any of the nine points between the POAG and healthy eyes after adjusting for IOP, age, and axial length (all P > 0.05). Similarly, there was no association between choroidal thickness and visual field defects (all P > 0.05). Our cross-sectional study indicated no significant difference in choroidal thickness between the POAG and healthy eyes, consistent with the results of the further meta-analysis involving 875 patients and 871 controls (weighted mean difference [WMD] for subfoveal choroidal thickness = -7.36 [95% confidence interval (CI): -24.39 to 9.67], WMD for mean macular choroidal thickness = 6.67 [95% CI: -2.45 to 15.79]). Six studies also provided data on average peripapillary choroidal thickness, and the pooled estimate was -8.15 (95% CI: -16.16 to -0.13, P = 0.046). However, considering that the precision of the OCT was 10 μm, this difference could have been caused by instrument error.
  
  
  CONCLUSIONS
  Our study of Chinese POAG patients, along with the meta-analysis, suggested that POAG was not significantly associated with a marked thinning or thickening of the choroid based on EDI-OCT measurements.
authors.affiliation: Zhongshan Ophthalmic Center, State Key Laboratory of Ophthalmology, Sun Yat-sen University, Guangzhou, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Zhongshan Ophthalmic Center, State Key Laboratory of Ophthalmology, Sun Yat-sen University, Guangzhou, People's Republic of China.
authors.forename: Xiulan
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000368:Aged; D044466:Asian People; D058452:Axial Length, Eye; D002829:Choroid / Q000473:pathology*; D003430:Cross-Sectional Studies; D005260:Female; D005902:Glaucoma, Open-Angle / Q000473:pathology*; D006801:Humans; D007429:Intraocular Pressure; D008266:Macula Lutea / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D018709:Statistics, Nonparametric; D041623:Tomography, Optical Coherence
keywords: choroidal thickness; optical coherence tomography; primary open-angle glaucoma