The Dry Eye Zone

Rebecca's Blog


Study: The "Lens Awareness Logger"


This is basically a study of a tool to be used in future studies, specifically about contact lens tolerance. You press a button every time you’re “aware” of your contacts. Apparently it worked well. Unsurprisingly, people are more aware just after putting them in and before taking them out, and people with symptoms are more aware of the lenses in the second half of the day than the first half.

So I would love to see some research done using this device as follows:

  • Track dry eye symptom awareness throughout the day amongst symptomatic dry eye patients and analyze the results!

  • Track scleral lens awareness throughout the day and analyze the correlations with things like dry eye type/severity, lens deposits, etc!

So many studies. But this MEASURE is just so much more directly relevant to patients’ needs than many other endpoints in studies (although of course they all have their place).

Dear research world: Comfortable vision is the name of the game, so you need to get more sophisticated in how you’re measuring the comfort side of things. That’s my two cents.

A wearable device to monitor ocular comfort. Read et al, Cont Lens Anterior Eye. 2019 May 13.



To develop and evaluate a wearable device (the lens awareness logger, LAL) to record subjective lens awareness during contact lens wear.


The LAL is a compact electronic event-logging device incorporating a tactile switch and belt-clip. Forty contact lens wearers (20 symptomatic and 20 asymptomatic) took part in a clinical evaluation of the LAL device. Subjects were instructed to wear their habitual soft contact lenses for 2 days (>8 h wear) and use the LAL device. Subjects activated the LAL device immediately prior to lens application and deactivated it following lens removal. If a subject became aware of their contact lenses at any point throughout the wear period they were instructed to depress the button on the LAL device.


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 (p < 0.0001). In addition, symptomatic subjects had a statistically higher percentage of LAL events in the second half of the lens-wearing day compared with asymptomatic subjects (p = 0.02). The LAL findings for each subject appear consistent across the two days (i.e. no fatigue or learning effect). The LAL device was well accepted by subjects with 38 of the 40 subjects reporting it was either 'very easy' or 'fairly easy' to use.


The LAL device was able to monitor ocular comfort throughout a period of contact lens wear and was well accepted by subjects. The ability of the LAL device to track ocular awareness events through the day, with high temporal resolution, means it is likely to be a key tool to further understanding of contact lens associated discomfort and dry eye disease.