How Material Properties Affect Soft Contact Lens Performance on the Eye
Authors: Moore, J., Lopes, B.T., Eliasy, A., Geraghty, B., Wu, R., White, L., Elsheikh, A., and Abass, A.
Journal: MDPI Bioengineering
Publication Date: Sep 2019
Diagram depicting the refraction process through the soft contact lens in a two-dimensional sketch for simplification purposes.
Summary:
If you wear contact lenses, you may be interested in our recent study, which looked at how different materials used in soft contact lenses can affect their performance on your eyes. Our aim was to evaluate the variation in the optical power of soft contact lenses when they are fitted on the eye, depending on the material properties of the lenses.
We conducted tensile tests on four different hydrogel materials, which are commonly used in soft contact lenses. We then used this data to create computer simulations of how these materials would perform when used in contact lenses with varying powers, from -10 to +20 diopters (D).
Our findings showed that the stiffness of the hydrogel material has a significant effect on the optical power of the lens when it is fitted on the eye. Stiffer materials were found to be more resistant to changes in optical power in the lower range of lens powers (from -10 to +5 D). This means that lenses made from stiffer hydrogel materials are more likely to maintain their prescribed optical power when worn, providing better vision correction for users.
However, as the lens power increases beyond +5 D, the choice of material has less of an impact on the lens's performance. At higher lens powers, the shape of the lens becomes more important in determining the final optical power on the eye.
Our research highlights the importance of considering the mechanical properties of hydrogel materials when designing soft contact lenses, as the material choice can significantly influence the lens's performance when fitted on the eye. This knowledge can help improve contact lens design, ensuring that users have the best possible vision correction when wearing their lenses.