title: Diurnal changes in retinal nerve fiber layer thickness with obstructive sleep apnea/hypopnea syndrome.
abstract: OBJECTIVE
  To compare the retinal nerve fiber layer (RNFL) thickness in the morning and evening in Thai patients with varying degrees of obstructive sleep apnea/hypopnea syndrome (OSAHS).
  
  
  METHODS
  In this cross-sectional study, potential OSAHS patients at Siriraj Hospital underwent polysomnography to determine the severity of OSAHS and an eye examination (including best corrected visual acuity, slit-lamp examination, and Goldmann applanation tonometry). RNFL thickness was recorded once in the morning and once in the evening, using spectral domain optical coherence tomography. Thickness was expressed as an average and given for each quadrant. Patients with ocular or systemic diseases that might affect RNFL thickness were excluded.
  
  
  RESULTS
  Forty-one eyes of 41 patients were classified into 4 OSAHS groups. The average and mean RNFL thickness in most of the four quadrants of the severe OSAHS group trended toward being less than those in the comparable quadrants of the other groups in both the morning and evening. In the moderate OSAHS group, the average RNFL thickness and temporal and superior quadrant thickness in the morning were significantly higher than in the evening (P=0.01, P=0.01, and P=0.03, respectively). In the severe OSAHS group, the inferior quadrant thickness in the morning was significantly higher than in the evening (P=0.03).
  
  
  CONCLUSIONS
  The RNFL thickness in the morning was higher than in the evening in moderate OSAHS.
authors: Department of Ophthalmology, Faculty of Medicine Siriraj Hospital, Bangkok 10700, Thailand.
authors: Niphon
authors: N
authors: Chirapapaisan
authors: Department of Ophthalmology, Faculty of Medicine Siriraj Hospital, Bangkok 10700, Thailand.
authors: Techawit
authors: T
authors: Likitgorn
authors: Department of Ophthalmology, Faculty of Medicine Siriraj Hospital, Bangkok 10700, Thailand.
authors: Mintra
authors: M
authors: Pleumchitchom
authors: Department of Ophthalmology, Faculty of Medicine Siriraj Hospital, Bangkok 10700, Thailand.
authors: Darin
authors: D
authors: Sakiyalak
authors: Department of Otorhinolaryngology, Faculty of Medicine Siriraj Hospital, Bangkok 10700, Thailand.
authors: Wish
authors: W
authors: Banhiran
authors: Department of Ophthalmology, Faculty of Medicine Siriraj Hospital, Bangkok 10700, Thailand.
authors: Manatsawin
authors: M
authors: Saiman
authors: Department of Ophthalmology, Faculty of Medicine Siriraj Hospital, Bangkok 10700, Thailand.
authors: Wanicha
authors: W
authors: Chuenkongkaew
keywords: optical coherence tomography; retinal nerve fiber layer thickness; sleep apnea/hypopnea syndrome