title: The effect of nocturnal CPAP therapy on the intraocular pressure of patients with sleep apnea syndrome.
abstract: OBJECTIVE
  Few studies have documented that nocturnal continuous positive airway pressure (CPAP) therapy is associated with an increase in intraocular pressure (IOP) in patients with severe obstructive sleep apnea syndrome (OSAS). We re-examined the effect of CPAP therapy on the IOP of OSAS patients.
  
  
  METHODS
  The IOP of two different groups of newly diagnosed OSAS patients was compared at their first sleep lab exam without CPAP treatment (non-CPAP treated group; n = 20) and at the second sleep lab exam with CPAP treatment (CPAP treated group; n = 31). The sleep lab exam (sleep period: from 11:00 p.m. until 6:00 a.m.) included IOP measurements, a complete ophthalmologic exam, and nocturnal hemodynamic recordings. The IOP was measured serially using rebound tonometer (IOP; ICARE® PRO) performed while in sitting and supine positions before, during, and after the sleep period. We compared the difference in IOP of CPAP and non-CPAP groups.
  
  
  RESULTS
  The mean IOP of the CPAP and non-CPAP groups measured in sitting position before the sleep period was 13.33 ± 2.04 mmHg and 14.02 ± 2.44 mmHg, respectively (p = 0.9). Assuming a supine position for 1 minute significantly increased the IOP by 1.93 mmHg and 2.13 mmHg for both the non-CPAP and CPAP groups (paired t-test; p = 0.02, p = 0.001 respectively), but this IOP rise showed no difference between the two groups. The IOP increased significantly further after 7 hours of sleep in the supine position, and the mean IOP of the CPAP and non-CPAP groups was 19.2 ± 5.68 mmHg and 19.69 ± 5.61 mmHg respectively (independent t-test; p = 0.74). The rise in IOP for both groups was not correlated with any hemodynamic parameters. Three OSAS patients with glaucoma treated with CPAP had mean IOP of 23.75 mmHg after 7 hours of sleep.
  
  
  CONCLUSIONS
  OSAS patients have a significant rise in IOP during the sleep period when comparing measurements before and after the sleep period; however, CPAP therapy did not affect the measured IOP. The presented findings suggest that in terms of IOP, CPAP is safe for non-glaucomatous patients, but this may not hold true for glaucomatous patients.
authors.affiliation: Goldschleger Eye Research Institute, Tel Aviv University, 53621, Tel Hashomer, Israel. dr.yuvalcohen@gmail.com.
authors.forename: Yuval
authors.initials: Y
authors.lastname: Cohen
authors.affiliation: The Institute for Fatigue and Sleep Medicine, Chaim Sheba Medical Center, 53621, Tel Hashomer, Israel.
authors.forename: Eyal
authors.initials: E
authors.lastname: Ben-Mair
authors.affiliation: The Institute for Fatigue and Sleep Medicine, Chaim Sheba Medical Center, 53621, Tel Hashomer, Israel.
authors.forename: Eyal
authors.initials: E
authors.lastname: Rosenzweig
authors.affiliation: The Institute for Fatigue and Sleep Medicine, Chaim Sheba Medical Center, 53621, Tel Hashomer, Israel.
authors.forename: Dalia
authors.initials: D
authors.lastname: Shechter-Amir
authors.affiliation: Goldschleger Eye Research Institute, Tel Aviv University, 53621, Tel Hashomer, Israel.
authors.forename: Arieh S
authors.initials: AS
authors.lastname: Solomon
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure; D045422:Continuous Positive Airway Pressure; D005260:Female; D005901:Glaucoma / Q000503:physiopathology*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D011187:Posture; D011446:Prospective Studies; D020181:Sleep Apnea, Obstructive / Q000628:therapy*; D011795:Surveys and Questionnaires; D014065:Tonometry, Ocular; D055815:Young Adult
keywords: CPAP; ICARE® PRO; Intraocular pressure; Obstructive sleep apnea syndrome; Rebound tonometer