Abstract: The present invention provides a device, a system, and associated methods for advantageously treating bodily tissues containing collagen, such as the cornea. The device is a topical device that, when placed over the target tissue, defines a space between an inner surface of the device and the tissue. The radiation-transparent device allows radiation to pass therethrough to the tissue during the radiation treatment. The device is believed to reduce heat loss, such as evaporative heat loss, from the tissue, thereby improving the tissue-heating efficiency of the radiation treatment. Typical radiation treatment parameters may thus be adjusted to provide a more gentle, yet highly efficient treatment using the inventive device. The gentle treatment reduces the likelihood of thermally traumatizing the treated tissue. While the invention has particular application in the area of corneal treatment, it may be used to prepare other tissues or substrates.