Efficacy of the Lancaster Red–Green Test for the Diagnosis of Superior Oblique Palsy

Abstract

The purpose of this study was to evaluate the usefulness of the Lancaster red-green test (LRGT) in patients with superior oblique palsy (SOP). The LRGT results of 42 adult patients with unilateral SOP (33 patients) or bilateral SOP (nine patients) were evaluated and compared with those of 21 patients who showed cyclotropia on Lancaster red-green test but did not have SOP (the non-SOP group). The degree of cyclotropia in primary position and downgaze, horizontal and vertical deviation, V pattern, and the presence of alternating hypertropia or reversal of hypertropia in the oblique field of gaze were analyzed using computer imaging software. The SOP groups showed a larger cyclotropia difference between primary position and downgaze than the non-SOP group. The bilateral SOP group showed a significantly larger degree of cyclotropia in the primary position and downgaze and a smaller amount of vertical deviation in the primary position than the unilateral SOP group. Four of nine patients with bilateral SOP and none of 33 patients with unilateral SOP showed an alternating hypertropia and reversal of hypertropia in the oblique field. The LRGT was found to be useful for the diagnosis of SOP and for the differentiation of unilateral SOP and bilateral SOP.