Material Science: Biomimetic surface enhancement

Monthly replacement contact lenses offer a replacement schedule that is preferred by many wearers. A summary of results from multiple surveys indicates that 32% to 36% of wearers use monthly replacement lenses.¹ Given this evident popularity, it is surprising that advancements in the technology for these lenses have lagged behind those for daily disposable lenses.

One current ‘state-of-the-art’ design for daily disposable lenses includes the patented Water Gradient Technology employed with delefilcon A (see Optician 04.03.22 and 01.04.22). This has resulted in a lens that provides both superior wettability and very high oxygen transfer.² This lens transitions from a highly breathable silicone hydrogel material at the core to a non-silicone hydrophilic polymer structure at the surface and has a Dk/t of 156 (at the centre of a -3.00DS lens) and a surface water content of nearly 100% (see table 1).²