A liquid, eye-instillable preparation comprises a viscosity-enhancing agent comprised of one or both of sodium hyaluronate and chondroitin sulphate, a preservative comprised of polyhexanide, and one or more carriers in which the agent and the preservative are dispersed. More specifically, the method includes ceasing all transmissions by the at least one AT during a duration corresponding to a duration used by an access node to transmit a superframe preamble, wherein the superframe comprises a plurality of physical frames. The plurality of switching elements are arranged with the antenna elements and transmission feed lines to, when selectively closed, electrically couple selected ones of the antenna elements and transmission feed lines to one another to generate an antenna configuration selected from a plurality of antenna configurations.