title: The effect of continuous positive airway pressure treatment for obstructive sleep apnea syndrome on the ocular surface.
abstract: OBJECTIVE
  To evaluate the effect of continuous positive airway pressure (CPAP) treatment for obstructive sleep apnea syndrome on the ocular surface.
  
  
  METHODS
  This is a prospective, sectional cohort study of 80 eyes of 40 patients diagnosed with obstructive sleep apnea syndrome. Routine ophthalmologic examination and ocular surface evaluation, including biomicroscopy, Schirmer 1 testing, tear break-up time measurement, ocular surface staining, and conjunctival impression cytology, were performed in both of each patient's eyes before and 4 months after starting CPAP therapy.
  
  
  RESULTS
  After CPAP therapy, increases in squamous metaplasia (Nelson classification: t = 0.34, P = 0.014) and Schirmer 1 score (t = 3.20, P = 0.008), and decreases in tear break-up time (t = -1.38, P = 0.008) in the right eyes were statistically significant, as compared with the pretreatment values. Although these parameters changed in a similar fashion in the left eyes, differences between the pre-CPAP and post-CPAP values were not significant.
  
  
  CONCLUSIONS
  The findings indicate that CPAP therapy increased ocular irritation, tear evaporation, and squamous metaplasia in the conjunctiva of the patients' right and left eyes. Although the parameters measured were similar in both eyes before CPAP therapy, these parameters changed significantly after CPAP therapy only in the right eyes. The observed differences between the right and left eyes require further investigation to determine the possible effects of sleeping position, CPAP mask displacement, and the other factors involved.
authors.affiliation: Departments of Ophthalmology, Faculty of Medicine, Ege University, Izmir, Turkey.
authors.forename: Emre
authors.initials: E
authors.lastname: Hayirci
authors.forename: Ayse
authors.initials: A
authors.lastname: Yagci
authors.forename: Melis
authors.initials: M
authors.lastname: Palamar
authors.forename: O K
authors.initials: OK
authors.lastname: Basoglu
authors.forename: Ali
authors.initials: A
authors.lastname: Veral
mesh_terms: D048430:Cell Shape; D048429:Cell Size; D003228:Conjunctiva / Q000473:pathology*; D045422:Continuous Positive Airway Pressure / Q000009:adverse effects*; D015352:Dry Eye Syndromes / Q000209:etiology*; D004569:Electroencephalography; D004576:Electromyography; D004585:Electrooculography; D005260:Female; D020397:Goblet Cells / Q000473:pathology*; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D008679:Metaplasia; D008875:Middle Aged; D010092:Oximetry; D017286:Polysomnography; D011446:Prospective Studies; D020181:Sleep Apnea, Obstructive / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D013666:Tears / Q000378:metabolism*