Thickness and Refractive Index Calculation of Contact Lenses Over Time Using Terahertz Imaging and Optical Coherence Tomography

Contact lenses are widely used for correcting refractive errors and treating various ocular disorders. However, their thickness and refractive index can change over time due to dehydration and mechanical stress, which can impact their optical performance and safety. In this study, we introduce a new method to measure these parameters using a combined terahertz and optical coherence tomography system. An iterative algorithm that combines information from multiple locations within the sample can provide the depth information and refractive index measurements for both THz and OCT frequencies. We applied this method to contact lenses and measured their thickness and refractive index at different time intervals. The results revealed significant changes in these parameters over time, highlighting the importance of proper monitoring. Overall, this novel method provides accurate and reliable measurements of contact lens thickness and refractive index over time, providing essential insights into their behavior in vivo.