Abstract
Purpose: :
Continuous positive airway pressure (CPAP) is now the treatment of choice for patients with Obstructive Sleep Apnea Syndrome (OSAS). Ocular side effects and adverse reactions, such as conjunctival irritation, are commonly reported with this device. The aim of this study was to determine the presence of signs of dry eye in OSAS patients treated chronically with CPAP.
Methods: :
We studied 24 patients (48 eyes; mean age: 51±12 years) who had been using CPAP for a period of 28 days for moderate to severe OSAS (BMI: 31±5 kg/m2; RDI = 54±19/h). Airway pressure was set at 16 cm/H2O and ventilation volume was 0.5L/min; environmental Temperature and Relative Humidity were monitored (T: 20±2.6°C and RH: 49±3.5 %). Each patient answered a dry eye 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 (baseline), and after 7 days and 28 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 before starting CPAP treatment. A significant increase in mean corneal fluorescein staining score was observed in the nasal area at day 7 and 28, as compared to baseline (P<.001). At day 28, the pattern of fluorescein staining was either diffuse (48%) or punctate (52%). Furthermore, the Schirmer test value decreased during the treatment, reaching significance at day 28 (3.4±1.8 mm/5min, P<.001). There was a concomitant significant decrease in BUT score. As determined by the questionnaire, patients reported dry eye symptoms after CPAP application.
Conclusions: :
Our results indicate that exposure to a contiunuous positive airway pressure may lead to symptomatic dry eye. Continuous airflow in those patients results in damage to the ocular surface epithelia and decreased tear volume. The use of a humidifier, to moisten the air, and customized masks, to avoid air leaking, is needed to prevent the appearance of dry eye in patients treated with CPAP.
Keywords: cornea: tears/tear film/dry eye • cornea: epithelium • cornea: clinical science