TEAR OSMOLARITY IN PEDIATRIC PATIENTS WITH CYSTIC FIBROSIS

Purpose: To evaluate the tear osmolarity in pediatric patients with cistyc fibrosis compaired with healthy control, and to correlate the osmolarity values with the genetic profiles. Methods: 30 eyes of 30 patients (20 males; mean age: 11 years, range: 8-16), with diagnosis of cistyc fibrosis and 30 eyes of 30 healthy patients age and sex matched, were enrolled. Only one eye of each patient was randomized to the analysis. The tear osmolarity was measured with the TearLab System (TearLab Corporation, San Diego, CA). Tear samples were collected from the lateral meniscus of the eye of each patient. All measurements were performed by the same investigator under similar testing conditions. The genetic mutations in patients with cistyc fibrosis were classified in severe (Class I-II-III) and mild (Class IV-V). Results: In the cistyc fibrosis group, the mean osmolarity value was 315.6 ± 30.5 mOsmol/L; in the control group the mean osmolarity value was 298.2 ± 16.4 mOsmol/L; the difference was statistically significant (t-Test; P < 0.001). The genetic mutation classes were significantly correlated with the osmolarity values (r= 0.64). Conclusions: Tear osmolarity is increased in children with cystic fibrosis, especially when a severe mutation is present. Screening for dry eye disease maybe indicated in patients with cistyc fibrosis.