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Purpose: To introduce a novel in vivo method (Visual Acuity Dry Up; VADU) for testing the visual performance during the dewetting of the pre-lens tear film on a contact lens (CL)., Methods: Thirty-nine subjects were fitted with daily disposable CL (Nelfilcon A). Visual performance and dewetting characteristics of the pre-lens tear film were simultaneously assessed using a modified multifunctional topographer (Keratograph 5 M, OCULUS Optikgeräte GmbH, Wetzlar, GERMANY) and the Non-Invasive Keratograph Dry-Up Time (NIKDUT) method. Measures were taken after five minutes and eight hours of CL wear and included the Visual Acuity Dry-Up Time (VADUT; time between last blink and visual breakdown) and the Visual Acuity Dry-Up Area (VADUA; dewetted CL area at visual breakdown) at one (VA +0.1logMAR ), two (VA +0.2logMAR ) and three (VA +0.3logMAR ) log units below maximal visual acuity (VA)., Results: Participants lost one, two or three log units of VA after 13.1 ± 17.4 s, 20.83 ± 21.81, 34.67 ± 29.11 (VADUT), corresponding to a dewetted CL area of 4.82 ± 6.64 mm², 9.5 ± 8.26 and 13.0 ± 8.68 (VADUA), respectively. Differences in VADUT und VADUA for all visual requirements were significant (all p < 0.05). VADUT and VADUA did not vary with CL wear duration (all p > 0.05). A median VA loss of one log unit occurred five seconds after the first dewetting., Conclusions: The novel VADU method can be used to analyze the role of the tear film stability on the visual performance during CL wear. Hereby, visual loss is quantified based on the threshold definition of the psychometric function., Competing Interests: Declaration of Competing Interest The authors declare that there are no conflicts of interest., (Copyright © 2020. Published by Elsevier Ltd.)

Purpose: To evaluate meibomian gland (MG) width and determine its impact on successful contact lens (CL) use and ocular health., Methods: A five-site study was conducted by recruiting 18- to 45-year-old subjects who had dropped out of CLs because of discomfort. CL dropouts were compared to age- and sex-matched successful CL wearers. Right eyes were evaluated for tear break-up time, tear meniscus height, MG expressibility, meibum quality, and meibography. Central MG widths were evaluated with a custom MATLAB program., Results: CL dropouts (n = 56) and successful CL (n = 56) wearers had similar grades for upper (p = 1.0) and lower (p = 0.22) MG atrophy, upper (p = 0.07) and lower (p = 0.89) MG tortuosity, and upper (p = 0.92) and lower (p = 0.97) MG widths. Upper eyelid MG widths were narrower than lower eyelid MG widths (p = 0.03). Upper and lower MG tortuosity (p < 0.001) and widths (p = 0.03) were associated, but not atrophy (p = 0.42). Lower eyelid MG widths were associated with MG expressibility (p = 0.01), but MG widths were not with any other factors., Conclusions: Successful CL wear does not appear to be clinically influenced by MG width or other measures of MG structural integrity. Lower eyelid MGs were wider than upper eyelid MGs and narrower lower eyelid MGs were associated with worse MG expressibility, suggesting that narrower MGs may produce abnormal meibum. Data also suggests that MG factors of both eyelids should be evaluated in practice., (Copyright © 2019 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: Contact lens (CL) dropout is estimated to be approximately equal to the number of new wearers per year, resulting in virtually no growth in the global CL market. The purpose of this study was to determine ocular and CL factors associated with CL dropout., Methods: This five-site study recruited subjects 18-45 years of age who had ceased CL wear within the past 6-12 months due to discomfort. Dropout subjects were compared to age- and sex-matched currently successful CL wearers. Each subject was administered a symptoms survey and a study-specific survey that queried general CL history and compliance. Clinical testing included non-invasive tear break-up time, tear meniscus height, blepharitis assessment, meibum quality and expression, and meibography., Results: A total of 56 matched-pairs were recruited. Dry eye was found to significantly increase a subject's odds of dropping out of CLs. The odds of dropping out of CLs was also significantly increased with each worsening grade of upper or lower eyelid meibomian gland (MG) plugging, upper eyelid meibum quality, and upper eyelid MG tortuosity. No other factors analyzed increased a subject's odds of dropping out of CLs., Conclusions: CL dropout may be precipitated by underlying dry eye symptoms, though most dry eye signs, with the exception of MG structure and function, had minimal predictive value for CL dropout. Nevertheless, evidence suggests that practitioners should screen for and educate CL patients about the importance of maintaining healthy MGs, which may potentially allow them to maintain comfortable CL use and increase their CL longevity., (Copyright © 2018 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.)

Purpose: Pilot study to investigate the feasibility of an axis-free correction approach of regular astigmatism using soft, bifocal contact lenses (CL)., Methods: The investigation covers an optical simulation and a pilot study for the assessment of visual performance (over refraction OR, monocular visual acuity VA). The power of the two zones was adjusted according to the power of the astigmatic meridians, individually. Subjective performance was assessed in 30 participants with a mean horizontal cylindrical component of J 0 =- 0.65±1.29 D (cylinder from -0.75 to -4.00 DC). OR and VA were measured directly after fitting the CL, after one hour and after 5days (3FUP)., Results: Evaluating the modulation transfer function, CL increased the Strehl ratio by 10% and the transferred spatial frequency was improved from 6.6 cpd to 21.3 cpd. Analysis of Sturm's interval revealed a residual astigmatism of D Ast =0.73 D. OR revealed a statistically significant reduction of spherical error between baseline and all follow up (ΔM=-2.14 D, p<0.001) and between the J 0 from baseline to 3FUP (ΔJ 0 =-0.46 D, p=0.04). Wearing the CL for 5days did not result in a significant difference of VA (ΔVA 3FUP =+0.01 logMAR, p=0.99)., Conclusion: Axis-free correction of astigmatism using bifocal CL resulted in reasonable performance based on computer simulation. Participants showed no clinically reduced visual acuity or contrast sensitivity. Further clinical studies are needed to show if this approach provides a good alternative to conventional astigmatic correction., (Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Purpose: This study was designed to develop a novel technique called non-invasive keratograph dry-up time (NIK-DUT), which used an adapted corneal topographer, to analyse in-vitro contact lens surface dewetting and the effects of combinations of lenses and lens care solutions on dewetting., Methods: Variables were assessed to optimise sensitivity and reproducibility. To validate the method, in-vitro dewetting of silicone hydrogel contact lenses (balafilcon A, comfilcon A, lotrafilcon A, lotrafilcon B and senofilcon A) was tested. All lens types were soaked in OPTI-FREE ® PureMoist ® Multipurpose Disinfecting Solution (OFPM) and Sensitive Eyes ® Saline Solution. The mean NIK-DUT, defined as drying of 25% of the placido ring measurement segments (NIK-DUT&#95;S25), was calculated for each lens/lens solution combination and a visual map constructed representing the time and location of the dry-up event., Results: Optimal conditions for NIK-DUT measurement included mounting onto a glass stage with a surface geometry of r=8.5mm, e=0, and measuring with high intensity red or white illumination. This method detected significant differences in contact lens dewetting with different lens soaking solutions. NIK-DUT&#95;S25 for all lenses was longer when pre-soaked in OFPM versus saline. Visual analysis showed that dewetting of contact lenses was not uniform across surfaces and differed between test solutions., Conclusions: NIK-DUT is suitable for detecting differences in dewetting among various contact lenses and lens-care combinations. NIK-DUT can quantify the dewetting of large areas of lens surfaces with little subjective influence. Lens care solutions containing surface-active wetting agents were found to delay surface dewetting of silicone hydrogel lenses., (Copyright © 2017. Published by Elsevier Ltd.)