title: Evaluation of choroidal thickness using spectral-domain optical coherence tomography in patients with severe obstructive sleep apnea syndrome: a comparative study.
abstract: OBJECTIVE
  To assess choroidal thickness in patients with severe obstructive sleep apnea syndrome (OSAS) and compare them with healthy controls, using spectral domain optical coherence tomography (OCT).
  
  
  METHODS
  In this observational, cross-sectional study, choroidal thicknesses of 23 newly severe OSAS patients and 23 body mass index- age- and sex-matched healthy subjects were measured using a high-speed, high-resolution frequency domain-OCT device (λ=840 nm, 26000 A-scans/s, 5 µm axial resolution). All patients underwent a complete ophthalmic examination before the measurements. OCT measurements were taken at the same time of day (9:00 a.m.), in order to minimize the effects of diurnal variation.
  
  
  RESULTS
  There was a statistically significant difference in median choroidal thickness between the OSAS patients (201 µm; range 145-237 µm) and the controls (324 µm; range 296-383 µm; P<0.001). There were significant differences at all measurement points (P<0.001 for all). The apnea-hypopnea index (AHI) values were more than 30 in all OSAS patients and the mean AHI was 48.57±6.54. The interexaminer intraclass correlation coefficient (ICC) for the mean choroidal thickness was 0.938 (95%CI, 0.908-0.985) and ICC was greater than 0.90 for all measurement points.
  
  
  CONCLUSIONS
  The decreased choroidal thickness of patients with severe OSAS might be related to the the autonomic disregulation associated with this disease. Further studies are needed to evaluate the etiopathologic relationship between choroidal thickness and OSAS.
authors.affiliation: Department of Ophthalmology, School of Medicine, Baskent University, Konya 42080, Turkey.
authors.forename: Aylin
authors.initials: A
authors.lastname: Karalezli
authors.affiliation: Department of Ophthalmology, School of Medicine, Baskent University, Konya 42080, Turkey.
authors.forename: Fatma Corak
authors.initials: FC
authors.lastname: Eroglu
authors.affiliation: Department of Pulmonary Medicine, School of Medicine, Baskent University, Konya 42080, Turkey.
authors.forename: Tulay
authors.initials: T
authors.lastname: Kivanc
authors.affiliation: Department of Pulmonary Medicine, School of Medicine, Baskent University, Konya 42080, Turkey.
authors.forename: Rusina
authors.initials: R
authors.lastname: Dogan
keywords: choroidal thickness; obstructive sleep apnea syndrome; optical coherence tomography