Changes in tear film physiology during soft contact lens wear

Abstract

Purpose : There have been many studies investigating the continuing effects of soft contact lens wear on ocular physiology, however longitudinal studies focusing on daily disposable soft contact lenses are sparse. The aim of this study was to independently evaluate changes in tear film physiology during modern daily disposable contact lens wear over a period of six months.

Methods : Ocular surface disease index (OSDI) and contact lens dry eye questionnaire (CLDEQ-8) were used for assessing symptoms. TearLab Osmolarity System (TearLab Corp, CA) was used to assess tear osmolarity, followed by tear meniscus height (TMH) and non-invasive Keratograph tear film break-up time (NIKBUT) measurements with K5M (Oculus Optikagerate GmbH, Germany) as well as fluorescein tear break-up time (FBUT) and ocular surface staining. Thirty-nine (26F/13M) healthy subjects aged 25.5±4.3 years (range from 20 to 37) were refitted with daily disposable contact lens (Delefilcon A) and monitored over a three visits within a six month period (baseline, 3 months and 6 months). Changes in the parameters were assessed with the Friedman test with post-hoc analysis using Wilcoxon test with the Bonferroni correction.

Results : There were no statistically significant differences observed in the OSDI and CLDEQ-8 scores. A continuing reduction in tear film osmolarity was observed ([mean±SD] 304±9, 302±9, and 298±5 mOsm/L for the baseline, 3-month and 6-month visit, respectively) and the changes were statistically significant between the baseline and the 6-month visit (p=0.002). There were no statistically significant differences observed in NIKBUT and FBUT between the 3-month and 6-month visits. Also, there was no statistically significant changes in TMH and corneal staining score. There were statistically significant changes in conjunctival staining score (χ²=8.55, p=0.036) noted with 0.65±0.5, 0.80±0.5, 1.0±0.5 for the baseline, 3-month and 6-month visit, respectively (all being clinically in a normal range).

Conclusions : Refitting subjects with modern daily disposable soft contact lenses resulted in small changes in ocular surface parameters. Continuing reduction in tear film osmolarity observed over time together with stable values of other measures of the ocular surface indicate that daily disposable soft contact lenses have achieved a level of performance that allows those lenses to minimally affect ocular physiology and comfort.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.