Short-term thermal changes before, during and after soft contact lens wear: an exploratory study

BACKGROUND: Infrared thermography allows non-invasive, real-time assessment of ocular surface temperature and represents a promising tool in contact lens (CL) research. Information regarding the short-term thermal changes before, during and after soft CL wear remains limited. This study investigated the short-term thermal response associated with daily disposable soft CL wear, the influence of CL material, and the repeatability of a portable thermographic camera. METHODS: A prospective study was conducted in 29 healthy young adults (mean age 23.5 ± 4.0 years, and 65.5% women) wearing two types of daily disposable soft CLs (stenfilcon A and omafilcon B). Ocular surface temperature was recorded at baseline, 1-min, 10-min and post-CL removal using a portable thermographic camera. Measurements were repeated one week later. Statistical analyses evaluated temperature changes following CL wear, thermal changes during the first 10 min of wear, and differences between CL materials. Repeatability was assessed using intraclass correlation coefficients (ICC) and Bland-Altman analyses. RESULTS: Baseline and post-CL temperatures differed significantly in both sessions (both p < 0.005). Significant thermal changes were also observed between the 1-min and 10-min time points after CL insertion (both sessions p < 0.05). No material-dependent differences were found (both sessions p ≥ 0.456). Baseline temperature showed poor repeatability (ICC = 0.043), whereas the temperature change between baseline and post-CL removal showed improved agreement (ICC = 0.438). Bland-Altman analyses confirmed wider limits of agreement for baseline measurements than for temperature change. CONCLUSION: Soft CL insertion induces significant short-term thermal changes before, during and after CL wear, independent of CL material. Although absolute baseline temperature measurements showed poor repeatability, the portable infrared thermographic camera demonstrated improved agreement for the temperature change between baseline and post-CL removal and may be a useful tool for evaluating thermal changes associated with CL wear.