Abstract
Purpose: :
To investigate the ability of a new class of di-block copolymers specifically tailored for hydrophilizing silicone surfaces to retard lipid accumulation on silicone hydrogel (SH) contact lenses.
Methods: :
Acuvue® OASYSTM (AO) (Johnson & Johnson) and PureVision® (PV) (Bausch & Lomb) lenses were presoaked in either saline or test solution containing the di-block copolymer for 24 hours. Lens hydrophobicity after presoak was assessed by quantifying the amount of Sudan IV Silicone Oil diffusion that occurred over two hours. For lipid analysis, presoaked lenses were incubated in 20 µg/mL NBD-cholesterol for 24 hours at 37oC. Adhered lipid was extracted from lenses with methanol and quantified via fluorometry. Lipid data reported as % prophylaxis relative to control, non-presoaked lenses.
Results: :
Pre-exposure to the di-block copolymer containing test solution resulted in a significant reduction in Sudan IV uptake in both lens types compared to saline (AO: 210 ± 51 vs 647 ± 80 ppm/lens, p < 0.05; PV: 364 ± 104 vs 794 ± 111 ppm/lens, p<0.05). Similar pre-exposure conditions resulted in a significant ability to retard lipid deposition on AO lenses (56% vs 0% lipid prophylaxis, p<0.05), but not on PV lenses (34% vs 30%, p = 0.29).
Conclusions: :
We have shown that the use of a di-block copolymer can reduce the hydrophobic nature of AO and PV contact lens materials. The ability to decrease surface and bulk hydrophobicity may translate into a significant ability to retard lipid deposition. Studies on additional SH lenses are ongoing to further investigate this function.
Keywords: contact lens • lipids • cornea: tears/tear film/dry eye