Natural pigments as multifunctional additives in contact lenses

Continuous exposure to blue light emitting devices as part of modern life leads to melatonin suppression that results in poor sleep quality and overall health. Contact lenses capable of blue light filtering could be used to mitigate this issue. This can be facilitated by using natural dyes to filter certain wavelengths from contact lenses. In this research, Curcuma Aromatica and Rubia Cordifolia were used to stain commercial contact lenses. This improved the blue light filtering capability and antibacterial resistance against Staphylococcus aureus and Pseudomonas aeruginosa bacteria. The UV Vis transmission spectra showed great blue light reduction for both natural pigments, C. aromatica being the better choice. The lenses showed a reduction of around 95 % in the blue light region while maintaining high transparency. Use of PVA improved the shelf life for C. aromatica, by providing better stability in both deionized water and contact lens storage solution. The lenses showed comparable contact angle and water retention properties, indicating that the additives retained the commercial contact lens’ properties. The MTT assay and Trypan blue assay indicated very good cell viability implying good biocompatibility of the lenses. Additionally, the anti-inflammatory effect of C. aromatica and C. aromatica + PVA dipped lenses strengthens the possibility of implementing them in further applications. The R. cordifolia dipped lenses seem to have improved inflammatory responses upon the addition of PVA. These lenses show great promise for protection against blue light from displays and other sources, offering a remedy to prolonged exposure to blue light.