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

Abstract

BackgroundSustained 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 methodsThis 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.ResultsEBTs 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).ConclusionEBT 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.

<p>Comparison and Evaluation of Prelens Tear Film Stability by Different Noninvasive in vivo Methods</p>

“… 39 Schafer et al reported that samfilcon A demonstrated a more wettable surface after blinking, compared to that of senofilcon A. 40 In our study, the value of the CA with samfilcon A was significantly lower than that of narafilcon A, indicating that samfilcon A had more wetting material than narafilcon A. This study is the first to evaluate the tear volume and prelens tear film stability in vivo, and the wettability of SCL materials in vitro.…”

Activity of Povidone in Recent Biomedical Applications with Emphasis on Micro- and Nano Drug Delivery Systems

“…Since pVP can absorb water, it also plays the role of a countermeasure against diarrhea in medicine [ 56 ]. As pVP has the ability of easily forming a film, it is used in contact lenses [ 57 , 58 ]. It has also been used as blood plasma substitute, but finally was replaced by another substance [ 59 , 60 ].…”

Contact lens, high refractive index, abbe number, hybrid materials, fabrication, enhancement

“…The two previous CLs patents have an improved gas permeability and are appropriate to the eye tissues. Recently, two CLs made of silicone hydrogel were integrated with Polyvinylpyrrolidone (PVP) to obtain a smooth water preserved CLs useful for people who are suffering from vision problems and working long time periods on computers (Schafer et al, 2018).…”