Contact lens wear results in the release of inflammatory mediators, according to a review published in Contact Lens and Anterior Eye. These inflammatory responses may be associated with mechanical trauma, hypoxia, and wearing schedules.
Researchers reviewed 34 clinical trials obtained through a PubMed database search to assess tear-borne inflammatory biomarkers during contact lens wear. Among the 34 trials mined, 30 examined the use of soft contact lenses, 3 investigated rigid permeable lenses, and 1 assessed scleral lenses. The team defined biomarker presence as changes in the molecular concentration of tears in contact lens wearers compared with a control group consisting of participants who did not wear contact lenses.
The investigators determined that contact lens use increases levels of various inflammatory molecules found in tears, including IL-1β, IL-6, IL-8, IL-17, LTB4, and MMP-9. They suggest that IL-17 could be integral to the perception of discomfort and found substantial variability between inflammatory biomarker levels—especially IL-6 and IL-8—which may be due to variations in population characteristics, storage conditions, and differences in how proinflammatory molecules were measured in the different studies.
The team noted that rigid gas permeable lenses yield a greater subclinical inflammatory response compared with soft contact lenses. Continuous- and daily-contact lenses also raised biomarker concentrations compared with daily-disposable lenses, which the team attributes to cytotoxicity caused by cleaning solutions and deposit collection on the lenses.
Orthokeratology lense use raised the level of tear inflammatory biomarkers and heightened the risk of ocular inflammation. This treatment may raise the risk of corneal epithelial damage and induce ocular inflammation in the long term, according to the report.
While the study confirms the release of these inflammatory mediators, “The relationship between these responses and contact lens-induced discomfort remains unclear, as the existing scientific evidence is still scarce,” according to the researchers. “More clinical studies are still needed to prove the impact of reverse geometry and scleral lens wear on the behavior of tear-borne biomarkers.”
Study limitations include a failure to differentiate between contact lens materials in one of the studies included in the review.
Pereira EI, Sampaio AP, Lira M. Effects of contact lens wear on tear inflammatory biomarkers. Cont Lens Anterior Eye. Published online April 21, 2022. doi:10.1016/j.clae.2022.101600.