Repeatability of lipid layer thickness using LipiView® following removal of contact lenses and its relationship to comfort.

Purpose: To assess the repeatability of lipid layer thickness (LLT) measurement using the LipiView® interferometer after daily disposable contact lens (CL) wear and correlation with ocular comfort in soft contact lens wearers.

Methods: A prospective study was conducted over two consecutive months, wherein CL wearers (n = 20) wore either Somofilcon A or Verofilcon A daily disposable CLs in a crossover design, switching lenses after 1 month. The pre-corneal tear film LLT was measured at the end of each month after CLs had been worn for at least 6 h. Using the LipiView® interferometer, three measurements of the LLT (average, maximum and minimum) were recorded. Subjects' symptoms were evaluated with the Contact Lens Dry Eye Questionnaire-8 (CLDEQ-8) and correlations sought between post-lens pre-corneal tear film LLT and symptoms.

Results: The average, maximum and minimum intraclass correlation coefficients (ICC) of LLT measurements at baseline were 0.57, 0.39 and 0.66, respectively, indicating poor (ICC < 0.4) to moderate (≥0.4, <0.75) repeatability. Coefficients of repeatability (CR) were 20.4, 24.8 and 20.8, respectively. After daily disposable CL wear, the ICC values were 0.66, 0.72 and 0.63 (indicating moderate repeatability), with CR values of 25.7, 32.0 and 23.3, respectively. Although all the ICC values of the pre-corneal LLT increased after daily disposable lens wear indicating improved repeatability, the CR values also increased, indicating larger spread of data. However, in both cases, these increases were not significantly different from baseline. There were no significant differences in pre-corneal LLT between the two lens types and no significant correlation with comfort scores (baseline: r = -0.11, p = 0.67; Verofilcon A lenses: r = 0.19, p = 0.45; Somofilcon A lenses r = 0.13, p = 0.62) for either lens.

Conclusions: The repeatability of average, maximum and minimum LLT measurements performed by LipiView remained stable during CL wear. There was no significant correlation between LLT and comfort scores.