Comparison of subjective and objective torsion in patients with acquired unilateral superior oblique muscle palsy

Abstract

BACKGROUND: To compare objective torsion, measured using fundus photography, and subjective torsion, measured with the Lancaster red-green test (LRGT) or double Maddox rod test (DMRT), in patients with acquired unilateral superior oblique palsy (SOP). METHODS: Full ophthalmic examinations, including the alternate prism and cover test, ductions/versions, three-step test, LRGT, DMRT and fundus photography, were performed in 35 consecutive patients (28 men and 7 women) (mean age, 50.4 ± 16.2 years) with acquired unilateral SOP. The correlation between the amount of torsion measured with fundus photography, the LRGT and DMRT was analysed using linear regression analyses. RESULTS: The LRGT, DMRT and fundus photography revealed extorsion in 16 (46%), 21 (91%) and 35 eyes (100%), respectively. There were no significant correlations between the amounts of torsion measured with the LRGT, the DMRT and fundus photography. There was a statistically significant correlation between SOP duration and the amount of torsion only when measured by the LRGT (p=0.0006). CONCLUSION: Objective extorsion may be found in all patients with acquired unilateral SOP, whereas subjective extorsion may be found in most patients with acquired unilateral SOP; the latter was detected more frequently with the DMRT than with the LRGT.