Effects of Oral Mucolytics on Tear Film and Ocular Surface

Purpose: To evaluate the effects of oral ambroxol on tear film and ocular surface. Methods: Twenty healthy male subjects with no ocular disease were recruited. Subjects were divided into 2 groups: a control group and an ambroxol group. Ambroxol hydrochloride was administered orally to the ambroxol group. The tear film and ocular surface were evaluated at baseline (10 AM), 12 PM, 6 PM, and 10 AM the next day. Visual analog pain scale, tear film break-up time, fluorescein corneal staining, Schirmer test, tear osmolality, and fluorescein clearance test were measured. Results: The mean visual analog pain scale score increased at 6 PM and 10 AM the next day in the ambroxol group (P = 0.007 and P = 0.018, respectively). The tear film break-up time did not show any significant change in the control group and shortened at 6 PM in the ambroxol group (P = 0.011). The fluorescein corneal staining scores increased at 6 PM in both groups (P = 0.007 and P = 0.004, respectively), and they were higher in the ambroxol group compared with control group at 10 AM the next day (P = 0.035). The mean tear secretion did not show a significant change in the control group and increased at 10 AM the next day in the ambroxol group (P = 0.022). In both groups, the tear osmolality increased at 6 PM (P = 0.009 and P = 0.005, respectively), but the tear osmolality in the ambroxol group was higher compared with control group at 6 PM (P = 0.043). Conclusions: Oral ambroxol may disturb tear film and ocular surfaces by attenuating the mucin layer of the tear film. This study was registered as Clinical Trial at ClinicalTrials.gov. as NCT01713179.