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Michel Guillon, Kishan Patel, Ruchi Gupta, Trisha Patel, Cecile A Maissa; Pre-contact lens tear film kinetic measurement repeatability under normal and adverse environmental conditions. Invest. Ophthalmol. Vis. Sci. 2017;58(8):3090.
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Traditionally, contact lens on-eye wettability has been assessed by measuring the non-invasive break-up time (NIBUT), which provides information only on the length of time that wettability is good. The measurement of tear film kinetics (TFK), which includes NIBUT, produces a global assessment of wettability over the full interblink period, while also characterizing the post-break destabilization. The purpose of this analysis was to evaluate the reliability of this new clinical technique.
The TFK of habitual DAILIES® TOTAL 1® (delfilcon A, Alcon) daily disposable contact lens wearers was measured in two different studies (n1= 90; n2=58) after 3 hours of conventional wear and a subsequent 3 hours of computer use in a controlled environment of 20% humidity. Digital videos were captured using non-invasive Tearscope illumination. The TFK (NIBUT, dehydration speed [DS], and minimum protected area [MPA]) was analyzed post hoc by masked investigators.
Overall (n=148), after 3 hours of wear, TFK characteristics were as follows: NIBUT (7.1±7.0 s), DS (0.28±0.66 mm2/s) and MPA (93.4±16.6 %). TFK characteristics remained unchanged after 3 hours in 20% humidity: NIBUT, 8.4±9.8 s; DS, 0.26±0.75 mm2/s, MPA 95.2±14.0 %). The TFK characteristics in the two studies were similar after 3 hours of wear and 3 hours in the dry environment. After 3 hours of wear, mean difference (95% CID) TFK values were: NIBUT, 0.9 s (-3.2, +1.4); DS, 0.00 mm2/s (-0.22, +0.22); and MPA, 2.0 % (-3.5, +7.4); after 3 hours in the dry environment, mean difference (95% CID) values were: NIBUT, 1.3 s (-4.5, +1.9); DS, 0.03 mm2/s (-0.28, +0.22); and MPA, 0.3% (-4.9, +4.3).
TFK after 3 hours of DAILIES® TOTAL 1® wear, characterized by a long NIBUT, slow dehydration upon the initial break and high surface coverage by the tear film, confirmed the good on-eye wettability of DT1; the findings recorded after exposure to dry eye conditions revealed DT1 robustness to adverse environmental conditions. The fact that similar findings were recorded in the two studies demonstrated consistency in TFK for DT1 and repeatability of the measurement method.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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