Abstract
Abstract: :
Purpose: Except for a photographic adaptation of the Kestenbaum limbal test used to assess traumatic sixth nerve pareses, there are no standardized techniques for measuring ocular motor restriction that have been used in a clinical trial. Most methods, including Hess screen, Lancaster red/green, and Goldman binocular single vision, tests of diplopia are cumbersome, variable in Ocular Myasthenia Gravis (OMG), require special equipment, and are not available in neuromuscular clinics. We compared portable methodologies for reproducible testing ocular muscle limitation to be used at multiple sites to study OMG. Methods: Two independent examiners prospectively compared ocular motor duction testing using duction grading (Scott and Kraft 1985), employing a scoring system of 0 to -5 (normal to a lack of muscle function, not reaching the midline, in 25% increments for grades, -1 to -4), Kestenbaum limbus test using a ruler to measure the number of mm’s of abduction, adduction, supraduction, and infraduction from the midline position, and the number of degrees of movement using an adapted cervical range of motion (CROM) device (Kushner 2000) in the evaluation of 20 patients (mean age 55 years, 9 men and 11 women), 8 with OMG, 11 with III or VI cranial nerve palsies, and 1 with dysthyroid ophthalmopathy. All subjects had diplopia, but 5 were orthophoric in primary gaze. Results: For Kestenbaum measures, the standard deviation of the differences (SDD) in ductions between examiners was 1.9 mm; approximately 95% of differences were within 4 mm. The intraclass correlation coefficient (ICC) was .67 (1.00 represents perfect agreement between examiners). For the CROM device the SDD was 7.1 degrees; approximately 95% of differences were within 15 degrees and the ICC was .64. Each examiner also repeated the CROM measurement and the SDD was less than 2 degrees for each examiner and the ICC’s were ≥.97. The repeatability within examiner was very high and repeatability between examiners considerably less. For duction grading the two examiners gave the same score in 83% of all measurements, and the weighted kappa statistic, which is the categorical data analogue of the ICC, was .81. Conclusion: The two methods that provide a continuous measure of ocular motor function, the Kestenbaum test and CROM, had similar inter-examiner repeatability as measured by the ICC. The categorical duction grading was more repeatable. Additionally, ptosis, poor vision, bifocal and progressive glasses limited the application of the CROM, making it less amenable to application a clinical trial.
Keywords: eye movements • eye movements