Abstract
Purpose :
To understand the neural mechanisms underlying contact lens discomfort (CLD). In Phase 1, the effects of 6-month contact lens (CL) wear on corneal sensitivity in neophytes who became symptomatic (NS) for CLD were investigated. In Phase 2, corneal sensitivity changes in these NS subjects when CL wear was first ceased for 3 months (washout) and then restarted for an additional 3-month period (re-challenge) were studied.
Methods :
The NS group were classified based on the Contact Lens Dry Eye Questionnaire-8 (CLDEQ-8) scores and comfortable wearing time during Phase 1. A control (C) group of non-CL wearers completed Phase 1 only. Corneal detection thresholds to cooling stimuli (approximately 22°C) were estimated at baseline (BL) by a modified Belmonte esthesiometer at study entry before fitting CLs and repeated at each month over Phase 1 (M1-M6) and during the Phase 2 washout period (WM1-WM3) and re-challenge period (RM1-RM3). Ten NS who completed both phases and 15 C subjects were included in the analysis. Repeated measures ANOVA and post-hoc tests with Bonferroni adjustment were used for data analysis.
Results :
Initially, in Phase 1, there was an increase in thresholds (becoming less sensitive) in both groups. The threshold at M4 was significantly different than BL and M1 (both p≤ 0.041) for the C group, but the NS group diverged in an opposite direction in M4-6 (Figure 1). In Phase 2, the threshold for the NS subjects increased during the washout period (WM1-WM3) and was significantly higher at WM3 compared to M1, M2 and M4 (all p≤ 0.046). Thresholds in Phase 2 tended to decrease (become more sensitive) during the re-challenge period (Figure 2).
Conclusions :
Corneal sensitivity in NS wearers tended to increase after an initial reduction and again after restarting CL wear following a washout period. These results demonstrate dynamic sensory responses to CL wear suggesting that altered sensory function may contribute to CLD development in these neophytes.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.