A system for monitoring and/or controlling tissue modification during an electrosurgical procedure includes an electrosurgical apparatus connected to an electrosurgical generator and configured to grasp tissue therebetween via a pair of jaw members. The system also includes an optical system having an optical source that directs light through tissue. One or more optical detectors analyze the light transmitted through and reflected back from the tissue and a processor utilizes this information to control the delivery of electrosurgical energy from the electrosurgical generator to the tissue.
