Associations of tear film characteristics with contact lens discomfort during daily disposable wear of contact lens polymers

<h2>Abstract</h2><h3>Purpose</h3> This study investigated tear film parameters during the wear of two daily disposable contact lenses composed of different polymers and examined their association with symptoms of contact lens discomfort. <h3>Methods</h3> A prospective, randomized, investigator-masked crossover study was conducted over two months with 20 participants wearing Somofilcon A or Verofilcon A daily disposable lenses. Tear meniscus height (TMH), non-invasive tear breakup time (NITBUT), and lipid layer thickness (LLT) were measured at the beginning of the study and after one month of wearing each lens type, both with lenses in-situ and after removal following at least six hours of wear. Symptoms were assessed using the Contact Lens Dry Eye Questionnaire (CLDEQ-8) and a visual analog scale (VAS). Differences in parameters between lens types and time points were analyzed using repeated measures ANOVA. Associations between tear film parameters and subjective comfort scores were assessed using Pearson's correlation coefficients. Statistical significance was set at p < 0.05. <h3>Results</h3> The NITBUT-average significantly improved with Verofilcon A (12.98 ± 4.27 s; p < 0.001) and Somofilcon A (12.30 ± 3.46 s; p < 0.001) compared to baseline (9.31 ± 3.29 s), with no significant difference between the lenses (p = 0.456). Significant changes in VAS comfort and CLDEQ-8 scores from baseline were observed for both lens types (p < 0.001). For Verofilcon A, CLDEQ-8 scores decreased, and VAS comfort increased while CLDEQ-8 scores negatively correlating with NITBUT-first break (r = −0.4637, p = 0.0455) and NITBUT-average (r = −0.5758, p < 0.001). i.e. a smaller CLDEQ-8 score (better comfort) associated with longer NITBUT.During Somofilcon A wear, CLDEQ-8 increased, and VAS comfort scores decreased, and VAS negatively correlated with NITBUT-first break (r = −0.5334, p = 0.018) and TMH (r = −0.4856, p = 0.0351). <h3>Conclusions</h3> Whilst better comfort with Verofilcon A was associated with improved NITBUT, correlations were moderate, and further studies are required to draw stronger conclusions. LLT showed no association with symptoms. Lens material and surface properties, along with ocular surface factors likely influence comfort outcomes.