Purpose: Non-invasive tear break up time (NITBUT) is a test commonly used by clinicians to measure the stability of the tear film. This study aims to compare the NITBUT of the Bausch and Lomb Biotrue Oneday (BT) Daily Disposable contact lenses against 3 other commercially available daily disposable lenses to see if BT can provide a more stable pre-lens tear film over the other 3 types of lenses at 12 hours of lens wear. Methods: Twelve existing contact lens wearers were recruited to wear 4 types of contact lenses each for a day of at least 12 hours. Other than BT, the other 3 test lenses were the daily disposable lenses made of etafilcon A (AV), narafilcon A (TE) and delefilcon A (DT1) materials. Each subject was assigned the lenses without knowing the brand of the lenses. Baseline NITBUT was first measured with no lens in the eye and pre-lens NITBUT was measured again at 12 hours after the lenses were worn. The NITBUT was measured using Oculus Keratograph 5M. This instrument measures the NITBUT objectively using infrared illumination which is invisible to the human eye and can prevent glare or bright light irritation during examination. Results: NITBUT was provided by the instrument as “first break” and “average break” values. In this study, the first break value was analyzed because that was the time when the break-up of tears was first detected by the instrument, and that matches with what the clinicians normally do in measuring NITBUT. The NITBUT for the nesofilcon A lens (BT) was longer than that for all the other 3 lens types in 10 out of the 12 subjects (83%). The mean TBUT for BT, AV, TE, DT1 was respectively 17.9 ± 4.3 sec, 9.5 ± 3.3 sec, 8.3 ± 5.9 sec and 8.8 ± 3.6 sec. Not only is the difference in NITBUT statistically significant (p<0.05, paired t-test – nesofilcon A (BT) Vs each of the 3 lens types), but also the NITBUT for BT is about double than that for all the other 3 types of lenses. Conclusion: The NITBUT for the nesofilcon A lens (BT) measured at 12 hours was about double than that for the other 3 lens types and the difference was statistically significant. The results suggested that the Biotrue Oneday provides a more stable pre-lens tear film than the other 3 types of daily disposable lenses at 12 hours of lens wear.

The bactericidal efficacy of three common sanitizers (100 or 200 ppm of sodium hypochlorite, 100or 200 ppm of n-alkyl(C12-C18)benzyldimethyl chloride, and 50 or 100 ppm of peroxyacetic acid) against Escherichia coli ATCC 10536 and Staphylococcus aureus ATCC 6538 was studied using the suspension test method at various exposure temperatures (4~40℃) and times(1~60min) under both dirty and clean conditions, respectively. During the suspension tests, sodium hypochlorite (200 ppm) showed higher bactericidal activity than the other sanitizers under clean conditions, with 5 log reductions against E. coli as well as S. aureus in the first 1 min of treatments at 4℃. However,the efficacy of sodium hypochlorite decreased markedly under dirty conditions due to its susceptibility to interfering substances. The efficacy of the n-alkyl(C12-C18)benzyldimethyl chloride increased considerable as the exposure temperature and time increased. The bactericidal efficacy of the n-alkyl(C12-C18)benzyldimethyl chloride might be less effective on low temperature, however, the longer time the sanitizer is in contact, the more effective the sanitization effect. Treatment with peroxyacetic acid (100 ppm) showed at least 5 log reduction against E. coli and S. aureus for 5min at 4℃ under both clean and dirty conditions. The efficacy of the peroxyacetic acid was not much altered by interfering substances and affected by changes in temperature or time.