A therapeutic agent based on a recombinant adenovirus which employs an osteocalcin promoter for the expression of thymidine kinase can be administered intravascularly to treat metastatic cancer, including osteosarcoma, breast cancer, prostate cancer, ocular melanoma or brain cancer. The frame can be configured to support at least one lens in a field of view of a wearer. The device includes a sensor mechanism that detects a force acting between the anchor connecting member and the webbing connecting member.