Length-tension recording system for strabismus surgery

Described is a technique for quickly assessing and graphically displaying the mechanical length-tension (L-T) characteristics of the passive tissues restraining eye movement and for measuring the patterns and magnitudes of active forces developed by the individual oculorotary muscles. Semiconductor strain gages mounted on the shanks of a custom-machined eye forceps and an ultrasonic method of making continuous duction measurements of the eye are proved feasible. When the forceps are interfaced with a dedicated microcomputer, the system provides a permanent. quantitative, L-T record displayed in real time. The instrumented L-T forceps system has provided a noninvasive means for quickly and simply assessing the mechanical underlying determinants of strabismus pathology in the office, the laboratory, and the operating room and can aid in the planning and immediate intraoperative alteration of strabismus surgery. A brief description of actual use and a few examples of clinical results are included from over 200 human records.