Alcon Inc. is researching a solution specifically designed to improve the wettability properties of silicone hydrogel contact lenses.
Alcon's researchers are studying a test solution containing a synthetic block co-polymer that uses proprietary polymer chemistry called poly (oxyethylene)-poly (oxybutylene), or EOBO.
According to Alcon, a test solution containing EOBO reduced the bulk and hydrophobicity to improve the hydrophilic properties of SiH lenses compared with a saline solution control1 . EOBO has an extremely high affinity for the hydrophobic areas of SiH CLs and targets sites on and in the lens to retain moisture.
Alcon's research compared the properties of the exploratory polymer solution with a saline solution in five different SiH lenses (Acuvue Advance and Acuvue Oasys, Vistakon; Biofinity, CooperVision; Pure Vision, Bausch + Lomb; and O2Optix, CIBA Vision). The lenses were soaked in either the exploratory polymer solution or saline and then subjected to three separate laboratory tests: captive bubble, sessile drop, and lipophilic dye diffusion.
The researchers wrote, "The first important result obtained in this study was that both the air (sessile drop contact angle method) and aqueous (captive bubble contact angle method) lens environmental conditions showed significant reductions in the advancing contact angles (improving the lens wettability) when the EOBO test solution was used to presoak the lenses." A lipophilic dye diffusion testing yielded a second important result: "When the [SiH] lenses were presoaked with the EOBO test solution, the hydrophobic dye diffusion kinetics at multi-hour time points was reduced compared [with] the control." Researchers noted that "This result indicated that the EOBO test solution improved the hydrophilic/water loving properties of the [SiH] lenses, even many hours after the initial exposure."