Ideally, contact lenses should sit on the cornea and create as little sensation as possible. Wearers should be so conditioned to the lens’ presence that they eventually lose most awareness of it. When they do become aware of the lens, that is often telling of a discomfort due to dryness or other flaws on the ocular surface. To monitor for these moments of awareness, researchers at The University of Manchester have developed a wearable, electronic, event-logging device, worn on a belt-clip. Patients are asked to click a button on the device every time they noticed their soft contact lenses. Consider it a step counter for ocular discomfort. After reviewing its potential, the researchers believe this monitoring device may be a key tool to further understanding contact lens-associated discomfort and dry eye disease.

To study its efficacy, the research team issued the devices to 40 subjects, who were instructed to use the device for two days while wearing their habitual soft contact lenses. Subjects activated the device immediately prior to lens application and deactivated it following lens removal.

They found the mean number of lens awareness events per hour was 1.3, although there was substantial variation between subjects (standard deviation 1.4). The distribution of lens awareness events throughout the contact lens wearing period showed significantly elevated awareness following lens application and prior to lens removal. Those elevations correlated with lens settling and end-of-day discomfort, the researchers highlight in the study abstract.

In addition, subjects already symptomatic for dry eye disease had a statistically higher percentage of awareness events as the day progressed. The findings for each subject appear consistent across the two days and the subjects rated it easy to use, the study said.