The impact of a hyaluronic acid derivative-containing care system on the wettability of PEG-coated rigid lenses

PURPOSE: This study investigated how a contact lens care solution containing a hyaluronic acid derivative (HAD) impacts wettability of rigid lenses, with and without polyethylene glycol (PEG) surface coatings when tested in vitro. METHODS: The adsorption of fluorescently labelled HAD and hyaluronic acid (HA) on to PEG and non-PEG coated lenses was compared by fluorescence quantification. The impact of HAD on sessile drop wettability was investigated on PEG and non-PEG coated lenses, which were cycled 300 times between an artificial tear solution (ATS) for 16 h and 8 h in a HAD or non-HAD containing solution. PEG-coated lenses were also rubbed with two commercial solutions over 30 cycles, to observe the impact on wettability. The total amount of lysozyme deposited on PEG-coated lenses when using these solutions after 30 cycles were also compared. Finally, to quantify the maintenance of the PEG coating, the amount of silicon detected nanometres under the lens surface when using either solution was determined using X-ray photoelectron spectroscopy. RESULTS: Greater amounts of HAD adsorbed onto rigid lenses compared to HA. Use of a HAD-containing solution improved the wettability of non-PEG coated lenses, being similar to uncycled PEG-coated lenses after 21 cycles. The wettability of PEG-coated lenses was maintained with the HAD-containing solution, with less lysozyme deposition and similar levels of silicon detected as uncycled lenses. In contrast, the non-HAD containing solution decreased wettability over cycles, with PEG-coated lenses being similar to non-PEG coated lenses after 90 cycles. These lenses also experienced greater amounts of lysozyme deposition, and a greater amount of silicon detected below the lens surface. CONCLUSIONS: Incorporation of HAD into a contact lens care solution has positive effects on wettability of both PEG and non-PEG coated rigid lenses. In contrast, using a non-HAD containing solution decreased wettability over time, even for PEG-coated lenses.