Evaluation of water content and water retention capacity of contact lens by optical reflective measurement

The performance values indicated by commercially contact lenses are generally based on the lens material and not on actual values based on actual wearing conditions. To explore the actual moisture content of contact lenses, we developed a fast optical non-contact measurement method. In the experiment, we designed a contact lens that conforms to the human eye structure, uses high-intensity white LEDs for projection illumination, calculates the water content by the intensity change of the reflected light, and derives the water retention of the contact lens through numerical processing. The experimental results show that the sample with the highest water content has the fastest rate of water retention, so the wearability is positively correlated with the water retention and negatively correlated with the water content. The results of this study can be used as reference information for industrial quality control and consumer purchases.