Hydrophobicity reduction in silicone hydrogel lenses boosts tear film interaction

Silicone hydrogel contact lenses contain significant hydrophobic areas, especially within their core material, according to a poster presented at the 2024 American Academy of Optometry Annual Meeting that found using lens care solutions like Opti-Free Puremoist (OFPM) effectively reduces these hydrophobic regions.

Researchers used lipophilic dye Sudan IV to identify hydrophobic areas on both the surface and inside the lenses. The study tested several popular contact lens materials, including Balafilcon A (PureVision), Balafilcon A (2) (PureVision 2 HD), Samfilcon A, Comfilcon A, and Fanfilcon A, as well as a hydrogel lens material, Ocufilcon D. They used a solution called OFPM and artificial tear solution to mimic how the lenses interact with tear film.

Although the surface hydrophobicity of silicone hydrogels was similar to that of the hydrogel reference, significant hydrophobic areas were detected within the core of the silicone hydrogels. OFPM effectively reduced these hydrophobic regions, particularly after lenses were soaked in artificial tear solution. The reduction was statistically significant across most materials except Samfilcon A.

Reference
Schurig S, et al. Evaluation of the Hydrophilicity of Silicone Hydrogels by Visualizing Hydrophobic Areas with Sudan IV. 2024 American Academy of Optometry Annual Meeting; November 6-9, 2024; Indianapolis, IN.