Relationship between cantho-limbal distance and degree of head turn in a Korean population

Objective To evaluate the relationship between cantho-limbal distance and the degree of head turn in Koreans. Design Prospective cross-sectional study. Participants Thirty patients without strabismus or nystagmus who had visited an ophthalmic clinic at a single medical center were included in the study. Methods The distance between the lateral canthus and lateral corneal limbus was measured using a 5 mm scale. The degree of head turn was measured with a goniometer when the cantho-limbal distances were 0, 5, and 10 mm. The degree of head turn was measured 3 times, and the mean value was used as the degree of head turn. Results When the cantho-limbal distances were 0, 5, and 10 mm, the degree of head turn values were 42.33, 30.47, and 2.53 degrees, respectively. The shorter the cantho-limbal distance, the higher the degree of head turn (r = −0.945, p < 0.01). The relationship was expressed as: Degree of head turn = −2.98 × cantho-limbal distance + 35.07. Conclusions Cantho-limbal distance can be used to estimate the degree of head turn. This method may be simpler and easier in a clinical situation than checking the degree of head turn with a goniometer.