A device for measuring a measured optical transmission path includes a first optical transmitter transmitting into the measured optical tramsmission path and a compensation transmitter transmitting into a compensation optical transmission path. The inner cover layer is comprised of a low acid ionomer blend which may or may not include a filler such as zinc-stearate. A method of augmenting soft tissue to provide long-term reduction of a skin defect, said method comprising stimulating collagen beneath the skin defect is further provided.