Purchase this article with an account.
Catherine A. Scheuer, Kyle Doty, Tesfaye Liranso, Susan Burke; Wetting Agent Retention and Release from Hydrogel and Silicone Hydrogel Contact Lenses. Invest. Ophthalmol. Vis. Sci. 2011;52(14):6487.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Wetting agents, which reduce surface tension (ST) to improve lens wettability, are included in contact lens disinfecting solutions (CLDS) in effort to keep lenses moist. The efficacy of wetting agents is dependent upon the ability to interact with lenses and release slowly during wear. An in vitro model was developed to investigate how wetting agents interact with silicone hydrogel and hydrogel contact lens materials and to evaluate how the interactions may affect wetting agent release profiles.
Etafilcon A (Acuvue2), alphafilcon A (SofLens Toric), balafilcon A (PureVision), senofilcon A (AcuvueOasys), and lotrafilcon B (O2Optix) lenses, after overnight equilibration in Hanks’ balanced salt solution (HBSS), were soaked eight hours in CLDS including Biotrue, fresh, sensitive, Replenish, and Clear Care. CLDS soaked lenses were rinsed with HBSS at the rate of tear film secretion. Rinsates were collected every 2h for 20h. To detect presence of wetting agents, ST of rinsates were measured by tensiometry. A statistical analysis was performed to evaluate differences in ST and wetting agent release of contact lens and CLDS combinations tested.
The ST of CLDS evaluated were between 39 - 45 mN/m; ST of HBSS was 77 mN/m. The ST of rinsates from all lens/CLDS solution combinations were initially reduced by 20 - 30 mN/m from that of HBSS. Over time, differences in extended presence of wetting agents were detected among various lens/CLDS combinations. In some cases, statistical differences were detected for up to 20 hours when compared to control lenses (Biotrue with senofilcon A and Replenish with etafilcon A). However, in other cases, statistical differences were observed for 8 or fewer hours (ClearCare with etafilcon A, Replenish with senofilcon A).
CLDS wetting agents are retained by hydrogel and silicone hydrogel lenses and are released over time with rinsing. The duration of retention depends upon the interactions between the wetting agent and lens surface and bulk chemical properties. Hydrophilic/lipophilic balance (HLB) value drives chemical interactions with lens material, while molecular weight influences penetration into lens bulk. The selection of CLDS providing extended release of wetting agents which reduce ST may lead to improved contact lens wettability.
This PDF is available to Subscribers Only