Novel in vitro method to determine pre-lens tear break-up time of hydrogel and silicone hydrogel contact lenses

TitleNovel in vitro method to determine pre-lens tear break-up time of hydrogel and silicone hydrogel contact lenses
Publication TypeJournal Article
Year of Publication2019
AuthorsWalther, H., L. N. Subbaraman, and L. Jones
JournalContact Lens and Anterior Eye
KeywordsArticle, artificial tear, contact lens, controlled study, copolymer, Daily disposable, daily disposable contact lens, delefilcon A, Deposition, equipment design, gel, hydrogel, in vitro study, lipid, mechanical stress, medical parameters, Model blink cell, nesofilcon A, NIBUT, physical chemistry, pre lens noninvasive break up time, priority journal, process development, silicone hydrogel, tear film, Tear film break-up time, unclassified drug
AbstractPurpose: To develop an in vitro model to determine pre-lens non-invasive break-up time (NIBUT) and to subsequently use this method to compare the NIBUT over contemporary daily disposable (DD) contact lenses (CL). Methods: Three silicone hydrogel (SH) and two conventional hydrogel (CH) DD CLs were incubated in an artificial tear solution (ATS). A model blink cell (MBC) was utilised to mimic intermittent air exposure. CLs were repeatedly submerged for 3 seconds (s) and exposed to air for 10 s over periods of 2, 6, 12, and 16 hours (h). NIBUTs (n = 4) were determined out of the blister pack (T 0 ) and at the end of each incubation period. Results: Overall, nesofilcon A showed the longest NIBUTs (p < 0.001). At T 0 , CHs revealed significantly longer NIBUTs (p ≤ 0.001) than SHs. After 2 h, nesofilcon A showed the longest NIBUT, however, this was only statistically significant compared with delefilcon A (p ≤ 0.001). After 6 h, nesofilcon A NIBUT was significantly longer than all other CLs (p ≤ 0.001). Etafilcon A showed a significantly longer NIBUT (p ≤ 0.001) after 12 h and delefilcon A had the longest NIBUT (p ≤ 0.001) after 16 h. Statistically significant (p ≤ 0.05) changes of NIBUT within the lens materials varied between time points. After 16 h, all CLs showed significant reductions in NIBUTs (p ≤ 0.001) in comparison to T 0 . Conclusion: NIBUT values reduced gradually over time and varying levels of deposition impacted measured pre-lens NIBUTs. While NIBUT of CH materials are longer immediately out of the blister pack, after tear film exposure, the NIBUTs obtained using this methodology became very similar. © 2018 British Contact Lens Association