Abstract
Purpose:
To analyze the differences in corneal sensitivity and in the tear levels of inflammatory molecules between symptomatic and asymptomatic hydrogel contact lens (HCL) wearers and its correlations.
Methods:
Sixty-six subjects were included in the study: 47 HCL wearers, divided into asymptomatic (n=23) and symptomatic (n=24) by means of the Contact Lens Dry Eye Questionnaire (CLDEQ) and 19 non contact lens wearers (control group). Corneal sensitivity (mechanical and thermal -hot and cold- thresholds) was measured using Belmonte’s non invasive aesthesiometer. The following tear molecules: EGF, Fractalkine, Interleukin (IL)-10, IL-1β, IL-1RA, IL-2, IL-4, IL-6, IL-8, MCP-1, TNF-α and MMP-9 were evaluated in tears samples (collected by a microcapillar from the lower tear meniscus) by multiplex bead analysis in a Luminex IS-100. Ocular Surface Disease Index (OSDI) questionnaire (symptoms reported while subjects were wearing HCL) was also administered. Measures and samples were obtained after at least 24 hours of non HCL use. Outcomes were compared among symptomatic HCL, asymptomatic HCL and non HCL wearers, and correlations between measured variables for each group were analyzed.
Results:
There were no significant differences among groups for any of the variables measured. The following significant correlations were found:1) in non HCL wearers group mechanical threshold correlated with: hot threshold (rho=-0.508, p<0.05), EGF (rho=0.626, p<0.01) and OSDI (rho=-0.656, p<0.01); hot threshold correlated with OSDI (rho=0.459, p<0.05) and cold threshold correlated with IL-8 (rho=-0.518, p<0.05); 2) in HCL wearers group (asymptomatic and symptomatic pooled) mechanical threshold correlated with hot threshold (rho=-0.311, p<0.05) and OSDI correlated with EGF (rho=-0.292, p<0.05); and 3) in asymptomatic HCL group OSDI correlated with EGF (rho=-0.497, p<0.05).
Conclusions:
No significant differences in corneal sensitivity or the tear molecules concentrations among the study groups were found. It may indicate either that HCL wear does not have a meaningful effect on some of the parameters measured, or that ocular surface recovers from the effect caused by HCL during the first 24 hours. However, correlations found prove the relation between symptoms, corneal sensitivity and the expression of some tear molecules of these subjects.
Keywords: 477 contact lens •
565 innervation: sensation •
490 cytokines/chemokines