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Sebastian Marx,1 Julia Eckstein,1 Wolfgang Sickenberger1,2 1JENVIS Research c/o Ernst-Abbe University of Applied Sciences Jena, Jena, Germany; 2Department of Optometry & Vision Science, Ernst-Abbe University of Applied Sciences Jena, Jena, GermanyCorrespondence: Sebastian MarxJENVIS Research c/o Ernst-Abbe University of Applied Sciences Jena, Carl-Zeiss-Promenade 2, Jena 07745, GermanyEmail s.marx@jenvis-research.comPurpose: The primary objective of this study was to evaluate the in vivo pre-lens non-invasive drying-up time of two types of daily disposable contact lenses (DDCLs) after 12 hours of wear.Methods: This prospective, randomized, single-center, cross-over pilot study evaluated 31 subjects aged 18– 44 years with normal eyes and good tear film stability who were adapted current soft contact lens wearers. Subjects wore nelfilcon A and stenfilcon A DDCLs for 12 hours each on two different days. Non-invasive video keratography drying-up time (NIK-DUT) videos of each eye were recorded 12 hours after lens insertion for about 25 seconds, with a 5-minute tear film recovery time allowed between video recordings of the right and left eyes to avoid bias. Post-blink time required to reach 15% distortion of the projected rings and the speed of break-up at 15 seconds post-blink were measured at each time point and on-eye wettability was determined by ring mire projection under white light illumination.Results: Mean time to reach 15% ring distortion was similar for nelfilcon A (19.25± 3.20 sec) and stenfilcon A (20.24± 3.02 sec) DDCLs but varied highly among subjects. The mean speed of break-up at 15 sec post-blink was 0.3± 0.38% distortion/sec (95% confidence interval [CI] 0.138– 0.365% distortion/sec) for nelfilcon A and 0.2± 0.23% distortion/sec (95% CI 0.048– 0.279% distortion/sec) for stenfilcon A DDCLs.Conclusion: Multifunctional topography allowed the objective evaluation of in vivo pre-lens tear film stability using ring mire projection. This dynamic method was simple, fast and non-invasive, enabling measurements of NIK-DUT and evaluating wettability over a large area, greater than the optical zone of the contact lens surface, for the entire inter-blink interval.Keywords: pre-lens tear film stability, wettability, daily disposable contact lenses, non-invasive break-up time, non-invasive drying-up time, corneal topography

Christiane Müller,1 Sebastian Marx,1,2 Julia Wittekind,2 Wolfgang Sickenberger2,3 1Jenalens Kontaktlinsenstudio GmbH, Jena, Germany; 2JenVis Research c/o Ernst-Abbe University of Applied Sciences Jena, Jena, Germany; 3Department of Optometry & Vision Science, Ernst-Abbe University of Applied Sciences Jena, Jena, GermanyCorrespondence: Sebastian MarxJenVis Research c/o Ernst-Abbe University of Applied Sciences Jena, Carl-Zeiss-Promenade 2, Jena 07745, GermanyTel +49 3641 205870Email s.marx@jenvis-research.comPurpose: To subjectively evaluate the in vivo tear film stability of three daily disposable contact lenses (DDCLs) using placido ring reflection at lens wear times of 5mins and 8 and 12hrs.Patients and Methods: This prospective, randomized, observer-masked, 3-way crossover study evaluated 28 subjects with good tear film stability. In vivo tear film stability was assessed for three DDCLs (nelfilcon A, etafilcon A, omafilcon A) on three different days over 12hrs of lens wear. Time to first distortion by non-invasive keratography drying-up time (NIK-DUTf) was assessed by reviewing the captured videos. Lens wettability was also graded subjectively by three investigators using a scale from 0 (no visible distortions) to 3 (distortions in more than one-third of the ring reflection zone). Medians were analyzed statistically.Results: Mean NIKDUTf at 8hrs was longer for nelfilcon A and shorter for etafilcon A and omafilcon A, but the differences were not significant. NIK-DUTf did not differ significantly among nelfilcon A, etafilcon A and omafilcon A DDCLs at all visits (p=0.36). Subjective wettability grades after 5mins, 8hrs, and 12hrs differed significantly for etafilcon A (P < 0.01) and omafilcon A (p < 0.01), but not for nelfilcon A (p = 0.05), DDCLs.Conclusion: Grading was sufficiently sensitive to differentiate the wettability performances of the three lens materials. Nelfilcon A maintained wettability over the wearing period, whereas etafilcon A material showed faster dewetting at 8 and 12hrs than at 5mins after lens insertion.Keywords: pre-lens tear film stability, wettability, NIK-DUT, drying-up time, daily disposable contact lenses, Keratograph 5M