Use of cold spray for relieving pain from local anesthetic injections in ocular surgery

To relieve pain from local anesthetic injections, the authors tried lowering the skin surface temperature by spraying a commercially available cold spray immediately before the injections. A noncontact thermometer was used to measure the thermal change of the skin surface. An esthesiometer was applied to determine the surface perception of the skin. Our basic experiments indicated that there was a relationship between the thermal change and the perception. When the surface temperature dropped to 10 degrees C, there was a definite decrease in the perception. Based on these findings, the authors applied the spray to 100 patients undergoing cataract surgery prior to both akinesia and retrobulbar anesthesia at a distance of 10 cm from the skin surface for 2 seconds, to be immediately followed by the injections. We found the spray to be effective in decreasing the pain due to these injections. Furthermore, there has been no major complications of the spray.