title: Continuous positive airway pressure therapy is associated with an increase in intraocular pressure in obstructive sleep apnea.
abstract: OBJECTIVE
  Several reports have demonstrated an association between glaucoma and obstructive sleep apnea (OSA), though the origin of this association remains unknown. In the present study, the influence of OSA and continuous positive airway pressure (CPAP) therapy on intraocular pressure (IOP) and ocular perfusion pressure (OPP) was examined.
  
  
  METHODS
  IOP, blood pressure, and pulse rate were measured every 2 hours during 24-hour sessions in 21 patients with newly diagnosed OSA. A first series of measurements was performed before CPAP therapy, and a second series was performed 1 month after the initiation of CPAP therapy. OPP was then calculated.
  
  
  RESULTS
  Baseline measurements showed a significant nycththemeral fluctuation in the average IOP, with the highest IOPs at night. After 1 month of CPAP therapy, the average IOP was significantly higher than baseline. The increase in overnight IOP was also significantly higher. A 24-hour IOP fluctuation of > or =8 mm Hg was found in 7 patients at baseline and in 12 patients during CPAP therapy. The mean difference between trough and peak IOP was 6.7 +/- 1.5 mm Hg at baseline and 9.0 +/- 2.0 mm Hg during CPAP therapy. Thirty minutes after CPAP cessation a significant decrease in IOP was recorded. There was a statistically significant decrease in mean OPP during CPAP therapy.
  
  
  CONCLUSIONS
  Patients with OSA demonstrated significant 24-hour IOP fluctuations, with the highest values at night. CPAP therapy causes an additional IOP increase, especially at night. Regular screening of visual fields and the optic disc is warranted for all patients with OSA, especially those treated with CPAP.
authors.affiliation: Department of Ophthalmology, Antwerp University Hospital and University of Antwerp, Antwerp, Belgium. stefan.kiekens@uza.be
authors.forename: Stefan
authors.initials: S
authors.lastname: Kiekens
authors.lastname: Veva De Groot
authors.forename: Tanja
authors.initials: T
authors.lastname: Coeckelbergh
authors.forename: Marie-José
authors.initials: MJ
authors.lastname: Tassignon
authors.forename: Paul
authors.initials: P
authors.lastname: van de Heyning
authors.lastname: Wilfried De Backer
authors.forename: Johan
authors.initials: J
authors.lastname: Verbraecken
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure; D002940:Circadian Rhythm; D045422:Continuous Positive Airway Pressure; D005260:Female; D006339:Heart Rate; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D020181:Sleep Apnea, Obstructive / Q000378:metabolism / Q000628:therapy*; D014065:Tonometry, Ocular