Comparing ocular muscle limitation tests for clinical trial use.

OBJECTIVE To evaluate portable methods for documenting ocular muscle limitation that might be used at multiple sites in a clinical trial. METHODS In a prospective consecutive case series, 2 examiners independently evaluated 3 methods of ocular muscle duction testing: a grading scale of 0 to -5 that is in clinical use, the Kestenbaum limbus test using a ruler to measure the millimeters of ocular movement, and an adapted cervical range of motion (CROM) device that measures ocular movement in degrees. Twenty consenting patients (mean age, 55 years) with diplopia, 8 with ocular myasthenia gravis, 11 with a cranial nerve III or VI palsy, and 1 with dysthyroid ophthalmopathy were studied. RESULTS For Kestenbaum measures, between examiners the standard deviation of the difference for all ductions was 1.9 mm (r = 0.75, P =.01); 95% of differences were 4 mm or less. For the CROM device, the standard deviation of the difference was 7.1 degrees; 95% of differences were 15 degrees or less (r = 0.73, P =.01). For each examiner, the CROM standard deviation of the difference was less than 2 degrees (r = 0.98, P =.01). For the grading scale, the 2 examiners had the same score in 85% of ductions (r = 0.92, P =.01). CONCLUSIONS The Kestenbaum test and the CROM device gave similar interexaminer repeatability. The repeatability for CROM measures for each examiner was high but was considerably less between examiners. The grading scale gave similar results between examiners.