title: Assessment of the retinal nerve fiber layer in individuals with obstructive sleep apnea.
abstract: BACKGROUND
  The effect of obstructive sleep apnea (OSA) syndrome in the peripapillary retinal nerve fiber layer (RNFL) thicknesses remains unclear. The purpose of this study was to assess RNFL measurements acquired using scanning laser polarimetry (SLP) and optical coherence tomography (OCT) in patients with OSA.
  
  
  METHODS
  The sample of this cross-sectional study included 40 OSA patients and 45 age-matched controls, consecutively and prospectively selected. All participants underwent at least one reliable standard automated perimetry (SAP) test, while RNFL measurements were obtained using the SLP and OCT. The OSA group was divided into 3 sub-groups based on the apnea/hypopnea index (AHI): mild, moderate, or severe OSA. SAP, SLP, and OCT outcomes were compared between the control and OSA groups. The relationship between AHI and RNFL parameters was also evaluated.
  
  
  RESULTS
  Age was not different between both groups. Mean deviation of SAP was -0.47 ± 0.9 dB and -1.43 ± 2.3 dB in the control and OSA groups, respectively (p = 0.01). RNFL thickness measured with OCT was similar between groups. OSA patients showed increased nerve fiber indicator (NFI; 20.9 ± 7.9 versus 16.42 ± 7.82; p = 0.01) and decreased superior average (59.74 ± 10.35 versus 63.73 ± 6.58; p = 0.03) obtained with SLP compared with healthy individuals. In the total sample, NFI and AHI were moderately correlated (r = 0.358; p = 0.001). In severe OSA subjects (n = 22), NFI and AHI had a Spearman correlation coefficient of 0.44 (p = 0.04).
  
  
  CONCLUSIONS
  RNFL thickness measured with OCT did not differ significantly between groups. Severe OSA was related to a reduction of the RNFL thickness assessed by SLP.
authors.affiliation: Department of Ophthalmology, IIS-Aragon, Miguel Servet University Hospital, Isabel la Catolica 1-3, 50009, Zaragoza, Spain.
authors.forename: Blanca
authors.initials: B
authors.lastname: Ferrandez
authors.affiliation: Department of Ophthalmology, IIS-Aragon, Miguel Servet University Hospital, Isabel la Catolica 1-3, 50009, Zaragoza, Spain. aferreras@msn.com.|University of Zaragoza, Zaragoza, Spain. aferreras@msn.com.
authors.forename: Antonio
authors.initials: A
authors.lastname: Ferreras
authors.affiliation: Department of Ophthalmology, IIS-Aragon, Miguel Servet University Hospital, Isabel la Catolica 1-3, 50009, Zaragoza, Spain.|University of Zaragoza, Zaragoza, Spain.
authors.forename: Pilar
authors.initials: P
authors.lastname: Calvo
authors.affiliation: Department of Ophthalmology, IIS-Aragon, Miguel Servet University Hospital, Isabel la Catolica 1-3, 50009, Zaragoza, Spain.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Abadia
authors.affiliation: University of Zaragoza, Zaragoza, Spain.|Department of Pneumology, Miguel Servet University Hospital, Zaragoza, Spain.
authors.forename: Jose M
authors.initials: JM
authors.lastname: Marin
authors.affiliation: Centro de Salud Seminario, Zaragoza, Spain.
authors.forename: Ana B
authors.initials: AB
authors.lastname: Pajarin
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000473:pathology*; D011446:Prospective Studies; D012165:Retinal Ganglion Cells / Q000473:pathology*; D057109:Scanning Laser Polarimetry; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis*; D041623:Tomography, Optical Coherence; D058609:Visual Field Tests
keywords: Obstructive sleep apnea; Optic nerve head; Optical coherence tomography; Retinal nerve fiber layer; Scanning laser polarimetry