In orbital surgery, the quantitative forced duction test is
important to estimate the restriction of entrapped extraocular
muscles or surrounding soft tissues. Metz and Yeaple3
reported simplified measurements of forced duction made
using a modified periodontal probe in operations for strabismus.
This probe is a quantitative length-tension measuring
device, but can record only two points (25 g and 30 g
of force). In contrast, the dial tension gauge that we
describe here can record traction force on a numerical scale.