A study from the School of Optometry and Vision Science at UNSW (Sydney) recently found 12 hours of lens wear lead to increased discomfort scores, regardless of when patients put their contact in. Whether they started at 8am, 9am or even after 10am, everyone reported improved discomfort during contact lens wear.

The researchers had 23 participants report their ocular discomfort with a 1-to-100 visual analogue rating scale during one day without contact lenses and then on three other days while wearing soft contact lenses for twelve hours. Contact lens wear began at a different time on each day, and the team evaluated the effect of start time on the change in discomfort during the wearing period.

The increased discomfort was significant for each of the three groups, and there were no statistically significant differences between start times. Based on the patient-reported ratings, the average change in discomfort over 12 hours without contact lenses was -0.3±3.5. The corresponding changes in discomfort during contact lens wear were 23.5±14.6 when starting wear before 8am, 16.8±11.0 when starting between 8am and 10am and then 22.7±8.4 when starting after 10am.

The researchers noted that the start time/discomfort relationship is highly variable and “does not, of itself, explain why contact lenses become uncomfortable during wear.”

They conclude that future studies should implement active monitoring of participant compliance to better understand discomfort.

Papas EB, Chiem A, Zhang G, et al. Temporal considerations in contact lens discomfort. Cont Lens Anterior Eye. August 29, 2020. [Epub ahead of print].