Abstract
Purpose :
Loss of comfort during the wearing day is greater with than without contact lenses and reported by both asymptomatic and symptomatic contact lens wearers. Typically, comfort is recorded for a single day or as an average over a period of wear, often one week. However, patients report having “bad days”, which would suggest that loss of comfort may vary from day to day. The purpose of the study was to understand the day to day variability in the change of comfort during the wearing day.
Methods :
A questionnaire was completed by the participants six times a day (lens insertion, 3, 6, 9, 12 hours of wear, lens removal) using SmartSurvey™, a time stamped secure survey software. Comfort at each time point was reported on a 100-point visual analog scale and the loss of comfort from lens insertion comfort was calculated. The survey was completed for one week in daily disposable (DD) (n=50) and two weeks (first week (MR1) and last week (MR4)) for monthly replacement (n=52) wearers using their habitual contact lenses. Day-to-day variability was measured using the within individual subject’s standard deviations of responses received for the study periods.
Results :
The lenses were the participants’ habitual correction (Wearing times (mean): DD 6.3, MR 6.5 days/week; DD 11.6, MR 11.9 hours/day). The variability in diurnal loss of comfort (removal- insertion) over a one-week period was significant for both replacement modalities (DD 14.0; MR1 10.8; MR4 9.9). The variability in diurnal loss of comfort was similar or greater for the DD than MR modality (DD vs. MR1 p=0.061; DD vs. MR4 p = 0.014) and similar between week 1 and week 4 for the MR modality (p=0.562). The loss of comfort variability increased over the course of the day: variability after 9 and 12 hours of wear was greater than after 3 hours of wear (DD 13.6 vs. 9.2, p=0.017; MR1 9.1 vs. 6.5, p=0.001; MR4 8.7 vs.5.3, p<0.001).
Conclusions :
The average day to day variability in diurnal loss of comfort within individual contact lens wearers, and therefore end of day comfort, was large (on average at least 10 points on a 100-point scale) regardless of the lens replacement modality. The clinical research implication is the necessity to collect subjective responses over several days to precisely quantify the mean subjective acceptance and its variability.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.