Silicone hydrogel contact lenses have become increasingly popular as much more oxygen can permeate them than traditional lenses, which promotes better ocular health. These lenses, however, are more susceptible to dryness and retaining depositions, which leads to as many as 40% of contact lens wearers to discontinue lens use. In a new study, Spadafora et al. have created a contact lens that has the potential to greatly improve eye dryness and discomfort for wearers.
Using a novel grafting method, they created a silicone hydrogel contact lens that is extremely wettable and absorbs less proteins from tears and ocular tissue.
“Usually when you put a droplet on the surface of a lens, the water beads up. In our work, we saw complete spreading out of the water on the new surface layer we created,” said author Heather Sheardown.
The authors created an anti-fouling model silicone hydrogel contact lens by modifying the surface using a phosphorylcholine-based polymer. The polymer was densely grafted to the surface of the lens using surface-initiated atom transfer radical polymerization. The surface polymer layer created a hydration layer and increased wettability and water content while decreasing protein depositions.
To improve the comfort for contact lens wearers, the next step will be translating these findings from the lab into the production process. Partnering with a contact lens company and coordinating large-scale human trials will be required to bring this methodology to the real-world.
“Comfort is a subjective thing,” said Sheardown. “Bunnies can’t tell you whether their contact lenses are comfortable.”
Source: “Antifouling silicone hydrogel contact lenses via densely grafted phosphorylcholine polymers,” by Alysha Spadafora, Myrto Korogiannaki, and Heather Sheardown, Biointerphases (2020). The article can be accessed at https://doi.org/10.1116/6.0000366.
