Jeffery Schafer

A meta-analysis of studies on cosmetically tinted soft contact lenses

Background Concerns regarding the safety of cosmetically tinted contact lenses have been reported in the literature. The purpose of this paper is to evaluate the safety of cosmetically tinted contact lenses in a large number of patients across six clinical trials that varied from 1 week to 3 months in duration. Methods Lenses tested included: Naturelle limbal ring daily disposable, Lacelle limbal ring daily disposable, Lacelle colored cosmetic daily disposable, Lacelle limbal ring planned replacement at 2 weeks, and Alamode traditional/annual colored cosmetic lens. The primary safety outcome was slit-lamp examination, including epithelial edema, epithelial microcysts, corneal staining, bulbar injection, limbal injection, upper lid tarsal conjunctival abnormalities, corneal neovascularization, and corneal infiltrates. High contrast logMAR visual acuity with lenses, and lens wearing time, movement, and centration, are also presented. Results A total of 871 subjects (1,742 eyes) and 23 clinical investigators participated in the six studies, with an average completion rate of 96.4% across all studies. The mean age of the patients was 26.8 ± 6.6 years, and 86.7% of participants were female. The total number of slit-lamp examinations across the six studies was 2,456 visits by eye (1,228 visits by patient). There were no slit-lamp signs > grade 2 for any finding, with the exception of corneal staining in one study. In this study, grade 3 corneal staining was noted in one eye (0.1%) at follow-up visit 1 and four (0.6%) of all eligible dispensed eyes at follow-up visit 2, with no eyes requiring medical treatment. No adverse events were reported during any of the trials. Conclusion The cosmetically tinted lenses evaluated in this meta-analysis appear to be safe when properly prescribed by an eye care professional and used in a compliant manner.

Evaluation of surface water characteristics of novel daily disposable contact lens materials, using refractive index shifts after wear.

Purpose Contact lens wearers today spend much time using digital display devices. Contact lens manufacturers are challenged to develop products that account for longer periods of time where blink rate is reduced and tear-film evaporation rate is increased, affecting both visual acuity and comfort. Two manufacturers recently introduced novel daily disposable contact lenses with high surface water content. The objective of the present study was to compare surface water characteristics before and after initial wear of recently introduced nesofilcon A and delefilcon A high surface water lenses with those of etafilcon A lenses. Patients and methods Twenty healthy subjects wore each of the three lens types studied in a randomly determined order for 15 minutes. After each wearing, lenses were removed and the surface refractive index (RI) of each lens was immediately measured. Results The mean RI of the unworn delefilcon A lens was 1.34, consistent with water content in excess of 80%. After 15 minutes of wear, the surface RI shifted to 1.43, consistent with its reported 33% bulk water content. In contrast, the mean surface RI of the nesofilcon A lens was 1.38, both initially and after 15 minutes of wear, and that of the etafilcon A lens was 1.41 initially and 1.42 after 15 minutes of wear. Conclusion The surface of the delefilcon A lens behaves like a high water hydrogel upon insertion but quickly dehydrates to behave like its low-water silicone-hydrogel bulk material with respect to surface water content during wear, while both nesofilcon A and etafilcon A lenses maintain their water content during initial wear. The nesofilcon A lens appears unique among high water lenses in maintaining high surface and bulk water content during wear. This is important because changes in surface RI due to dehydration are reported to lead to visual aberration affecting user experience.

Use of a novel extended blink test to evaluate the performance of two polyvinylpyrrolidone-containing, silicone hydrogel contact lenses

Background Sustained digital display viewing reduces eye blink frequency and tear film stability. To retain water and preserve a smooth optical surface, contact lens manufacturers have integrated the humectant polyvinylpyrrolidone (PVP) into silicone hydrogel contact lenses. In this study, extended blink time (EBT) was used to assess visual stability over a prolonged blink interval of two PVP-containing silicone hydrogel lenses, samfilcon A (SAM) and senofilcon A (SEN). Materials and methods This randomized, bilateral, masked, crossover study assessed lens performance in ten subjects after 16 hours of wear. EBT, ie, the time elapsed between cessation of blinking and blur-out of a threshold letter on the acuity chart, was measured. At the end of the wear period, subjects reported duration of computer use and rated visual quality (VQ) and comfort while wearing the assigned lens, and the investigator evaluated lens surface wetting characteristics. Each lens was removed and immediately weighed to determine total water content. Results EBTs were 10.42 seconds for SAM and 8.04 seconds for SEN (p = 0.015). Subjective ratings of VQ after 16 hours of wear were 84.6 for SAM and 74.4 for SEN (p = 0.049). Comfort ratings were 85.9 for SAM and 80.2 for SEN (p > 0.05). Median times of computer use were 6–8 hours for both lens types. Post blink, 70.0% of SAM and 30.0% of SEN lenses were completely wet (p = 0.021). Total water content after wear was 43.7% for SAM and 35.5% for SEN (p < 0.001). Conclusion EBT measurement indicated more stable vision with the PVP-containing SAM polymer compared with the PVP-containing SEN polymer. The SAM polymer also demonstrated better surface wetting and maintained higher water content after a prolonged period of wear. EBT can be valuable in assessing vision stability of patients after hours of computer use.

Differences in daily disposable circle lens performance characteristics

License. The full terms of the License are available at http://creativecommons.org/licenses/by-nc/3.0/. Non-commercial uses of the work are permitted without any further permission from Dove Medical Press Limited, provided the work is properly attributed. Permissions beyond the scope of the License are administered by Dove Medical Press Limited. Information on how to request permission may be found at: http://www.dovepress.com/permissions.php Clinical Optometry 2014:6 37–42 Clinical Optometry Dovepress

Patient satisfaction with a novel one-step hydrogen peroxide solution.

Purpose We aimed to evaluate the product performance of a novel one-step hydrogen peroxide cleaning and disinfecting solution, PeroxiClear (“Test” solution), when used by habitual Clear Care users to bilaterally clean and disinfect their soft contact lenses, for approximately 2 weeks. Methods This was a 2-week, open-label, bilateral eye study designed to include subjects ranging in age from 18 to 55 years, inclusive. All subjects were habitual users of the Clear Care peroxide regimen for cleaning, disinfecting, and storage of their soft contact lenses, for at least 6 months prior to enrolling in the study. Subjects were examined at two study visits: a screening/dispensing visit and a 2-week follow-up visit. The primary end point, patient preference for the Test solution, was evaluated with an online survey administered after 7 days of using the Test cleaning and disinfecting solution. Respondents could answer questions with neutral or nonneutral responses (better or worse). Statistical analyses were conducted to compare differences for nonneutral responses. Results Of the 299 eligible subjects enrolled, 297 completed the study, conducted at 21 sites by 21 investigators in the United States. A significantly higher proportion of nonneutral respondents reported the Test solution was better overall (85.9%) than their habitual contact lens solution (14.1%) (P<0.001). The proportion of subjects who preferred the Test solution over their habitual solution was significantly higher for each of the preference questions regarding comfort (85.4% vs 14.6%), moistness (90.0% vs 10.0%), cleanness (91.6% vs 8.4%), and clarity of vision (85.8% vs 14.2%). Conclusion After 7 days of using the Test cleaning and disinfecting solution, survey results indicated high levels of patient satisfaction and preference over the habitual solution, particularly in the areas of comfort, moisture, and cleanness.