Unique Lens Material Helps Minimize Lens Wearers' Discomfort
New research suggests that a novel silicone hydrogel material could help keep contact lens wearers from discarding their contacts due to discomfort caused by feelings of dryness, the most commonly reported reason people discontinue contact lens wear. Using a controlled clinical model for evaluating dryness, researchers report that patients experienced less discomfort while wearing contact lenses made with senofilcon A (ACUVUE OASYS. Brand Contact Lenses) than they did either while wearing no lenses or while wearing their usual contact lenses in a controlled adverse environment. The findings appear in the current issue of Current Medical Research and Opinion.
Contact lens wearers frequently complain of sensations of eye discomfort and dryness associated with wearing their lenses. Roughly 51 percent of lapsed lens wearers cite discomfort as the primary reason they discontinued wearing their lenses. Forty percent attribute their contact lens abandonment to dryness.
"Most soft contact lenses materials have demonstrated a susceptibility to environmental factors which can lead to clinical symptoms normally associated with ocular dryness," says Sheila Hickson-Curran, Director, Medical Affairs, Vistakon. "In addition to humidity, variables such as air movement (wind), temperature, and blink-rate altering visual activities such as reading and computer use can exacerbate signs and symptoms of dryness in contact lens wearers."
"Senofilcon A has previously shown promising results for reducing lens-wear related symptoms of dryness and discomfort," she adds. "This study shows that contact lenses made with senofilcon A may be superior to other soft lens materials in terms of minimizing dryness symptoms associated with exposure to adverse environmental conditions. Senofilcon A was also found to reduce discomfort symptoms even beyond that experienced with no lens, indicating a protective effect."
About the Study
The purpose of the study was to compare the ability of ACUVUE OASYS (senofilcon A) contact lenses to wearer's habitual contact lenses to provide relief from ocular discomfort during contact lens wear in adverse environmental conditions.
Researchers used the Controlled Adverse Environment (CAE) model, a proprietary state-of-the-art model for conducting ocular dryness studies, to investigate dryness during contact lens wear. Typically incorporated into clinical trials studying ocular dryness, the CAE is used to exacerbate dryness symptoms in a reproducible, controlled manner by closely regulating humidity, temperature, airflow, lighting, and visual tasking. Acute ocular drying conditions are optimized in the CAE by using appropriate exposure times and requiring subjects to perform a visual task such as reading or working on a computer.
Eleven participants completed a single-center, double-masked, randomized, cross-over, CAE study. Participants were current, successful contact lens wearers with histories of ocular discomfort during lens wear in windy or dry environments.
Study participants underwent a total of three 75-minute CAE exposures during a two-week period -- once with no lenses, once wearing a new pair of their habitual contact lenses, and once wearing senofilcon A contact lenses. Subjects were not permitted to use rewetting drops or tear substitutes for at least 12 hours prior to visits and were not allowed to wear their contacts for at least 72 hours prior to visits.
When wearing senofilcon A contact lenses, study participants reported significantly lower subjective ocular discomfort scores during exposure to a controlled adverse environment than they did when wearing their habitual contact lenses. Participants reported better mean discomfort scores across all time points during CAE exposure while wearing senofilcon A lenses (1.62 plus or minus 0.71 points) than they did while wearing their habitual contact lenses (2.21 plus or minus 0.80 points, p <0.05). Senofilcon A lenses also yielded significantly better mean overall discomfort scores versus no lenses (2.73 plus or minus 0.79 points, p<0.0001)