Measurement of ocular cyclotorsion in superior oblique palsy using a single Maddox rod.

BACKGROUND: To describe a modified technique to measure ocular cyclotorsion using only 1 Maddox rod and compare it with the traditional double Maddox rod test (DMR).

METHODS: Ocular cyclotorsion was prospectively measured in 48 consecutive patients with superior oblique palsy. Four measurements were taken; 2 using 2 Maddox rods: (A) a red rod in front of the affected eye and a white rod in front of the fellow eye and (B) red rod in front of the sound eye and red in front of the affected eye. Two additional sets of measurements were taken using 1 red Maddox rod in front of 1 eye only, where horizontal lines in the room served as a reference: (C) the red rod in front of the affected eye and (D) the red rod in front of the sound eye.

RESULTS: Mean ocular cyclotorsion in 48 patients was 6.7°, 6.8°, 6.6°, and 6.1° in measures A, B, C, and D, respectively. The agreement between A and C did not differ statistically, whereas the agreement between B and D was statistically different (P < 0.0001). There was high repeatability in both comparisons.

CONCLUSIONS: Ocular cyclotorsion may be measured using a single Maddox rod instead of two. It is simpler to conduct than the DMR.