title: Retinal nerve fiber layer in primary open-angle glaucoma with high myopia determined by optical coherence tomography and scanning laser polarimetry.
abstract: BACKGROUND
  Fundus changes associated with high myopia (HM) may mask those associated with primary open-angle glaucoma (POAG). This study aim to determine the characteristics of RNFL thickness changes in patients with both POAG and HM and compare these to changes in patients with only HM. The diagnostic capabilities of both OCT and GDxVCC in this subset of patients are also evaluated.
  
  
  METHODS
  Twenty-two eyes with POAG and HM (spherical equivalent (SE) between -6.0 and -12.0 D) were evaluated, and 22 eyes with HM were used for comparison. Characteristic retinal nerve fiber layer (RNFL) thickness profiles in patients with POAG and HM were examined using optical coherence tomography (OCT) and scanning laser polarimetry with variable corneal compensation (GDxVCC), and the diagnostic capabilities of these imaging modalities were compared. RNFL parameters evaluated included superior average (Savg-GDx), inferior average (Iavg-GDx), temporal-superior-nasal- inferior-temporal (TSNIT) average, and nerve fiber indicator (NFI) on GDxVCC and superior average (Savg-OCT), inferior average (Iavg-OCT), nasal average (Navg-OCT), temporal average (Tavg-OCT), and average thickness (AvgThick-OCT) on OCT (fast RNFL scan). Visual field testing was performed and defects were evaluated using mean defect (MD) and pattern standard deviation (PSD).
  
  
  RESULTS
  The RNFL parameters (P < 0.05) significantly different between groups included Savg-GDx, Iavg-GDx, TSNIT average, NFI, Savg-OCT, Iavg-OCT, Tavg-OCT, and AvgThick-OCT. Significant correlations existed between TSNIT average and AvgThick-OCT (r = 0.778), TSNIT average and MD (r = 0.749), AvgThick-OCT and MD (r = 0.647), TSNIT average and PSD (r = -0.756), and AvgThick-OCT and PSD (r = -0.784). The area under the receiver operating characteristic curve (AUROC) values of TSNIT average, Savg-GDx, Iavg-GDx, NFI, Savg-OCT, Iavg-OCT, Navg-OCT, Tavg-OCT, and AvgThick-OCT were 0.947, 0.962, 0.973, 0.994, 0.909, 0.917, 0.511, 0.906, and 0.913, respectively. The NFI AUROC was the highest value.
  
  
  CONCLUSIONS
  RNFL thickness was significantly lower in all but the nasal quadrant in patients with POAG and HM, compared to patients with only HM. Measurements with OCT and GDxVCC were well-correlated, and both modalities detected RNFL thickness changes. However, GDxVCC was better than OCT in detecting POAG in HM patients.
authors.affiliation: Center of Glaucoma, Department of Ophthalmology, the First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, China.
authors.forename: Xiao-en
authors.initials: XE
authors.lastname: Wang
authors.forename: Xiao-yu
authors.initials: XY
authors.lastname: Wang
authors.forename: Yang-shun
authors.initials: YS
authors.lastname: Gu
authors.forename: Zhu
authors.initials: Z
authors.lastname: Huang
mesh_terms: D000328:Adult; D005260:Female; D005902:Glaucoma, Open-Angle / Q000473:pathology*; D006801:Humans; D008297:Male; D009216:Myopia / Q000473:pathology*; D009412:Nerve Fibers / Q000473:pathology*; D055351:Retinal Neurons / Q000473:pathology*; D057109:Scanning Laser Polarimetry / Q000379:methods*; D041623:Tomography, Optical Coherence / Q000379:methods*