Abstract
Purpose: :
Continuous positive airway pressure (CPAP) is the chronic treatment of choice for patients with Obstructive Sleep Apnea Syndrome (OSAS). Symptomatic dry eye has been reported after using CPAP devices with nasal facial masks, thus compromising compliance to the treatment. The aim of our research was to study the ocular surface selectively in patients using devices with nasal insufflation (TNI) in order to minimized air leaking that is believed to cause the ocular dryness.
Methods: :
We studied 34 patients (68 eyes; mean age: 49±15 years) who had been using CPAP for a period of 60 days for moderate to severe OSAS. Airway pressure was set at 16 cm/H2O and ventilation volume was 0.5L/min; environmental Temperature and Relative Humidity were monitored. Each patient answered a questionnaire and underwent a complete ocular examination. Clinical measurements of tear function (BUT, Schirmer 1) were completed. Corneal surface integrity was determined by means of fluorescein staining. Patients were evaluated before starting the treatment at day 0 and after 7, 28 and 60 days of treatment. Individuals with ocular surface diseases, contact lens or ocular drug users were excluded from the study.
Results: :
No symptoms and signs of dry eye were detected in OSAS patients at day 0 and after 7 and 28 days of treatment. A significant increase in mean corneal fluorescein staining score was observed in the nasal area at day 60, as compared to baseline (P<.001). The Schirmer test value decreased during the treatment, reaching significance at day 60 (3.9±0.9 mm/5min, P<.001). There was a concomitant significant decrease in BUT score. As determined by the questionnaire, patients reported symptoms of ocular and nasal dryness after 2 months of CPAP application.
Conclusions: :
Our results indicate that long-term exposure to a continuous positive airway pressure via nasal cavities may lead to dry eye with damage to the ocular surface epithelia and decreased tear volume. More studies are needed to investigate the nasal mucosa reaction to a continuous airflow and to understand the molecular interconnection between nasal and ocular surface epithelia.
Keywords: cornea: tears/tear film/dry eye • cornea: epithelium • cornea: clinical science