We have measured the amplitude of ocular counterrolling (OCR) and the change in vertical deviation in the Bielschowsky head-tilt test (BHT) in 23 cases of unilateral superior oblique palsy. OCR was measured with a photographical method, using limbal, conjunctival vessels as landmarks. Average OCR of the healthy eye was 5.4 ± 2.4 (SD) deg either side, at 45 deg of body-tilt. BHT and OCR (of the healthy eye) were not related in the group as a whole. An important perturbing factor was the duration of the palsy. To clarify the relation between BHT, OCR and duration of palsy, the BHT/OCR ratio was calculated in each patient. Six cases with a palsy of presumed recent onset had BHT/OCR ratio of 0.57 ± 0.09, while twelve cases of long-standing palsy had a BHT/OCR ratio of 1.04 ± 0.71. This means that in cases of recent onset, the relation was relatively fixed. All high BHT/OCR ratio's occurred in long-standing palsies, whether acquired or congenital. In our opinion, disproportionately large amplitudes in the Bielschowsky head-tilt test are caused by secondary innervational changes or contractures.

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Vision Research
Department of Ophthalmology

Simonsz, H., Crone, R. A., Meer, J., Merckel-Timmer, C. F., & van Mourik-Noordenbos, A. M. (1985). Bielschowsky head-tilt test-I. Ocular counterrolling and Bielschowsky head-tilt test in 23 cases of superior oblique palsy
. Vision Research, 25(12), 1977–1982. Retrieved from http://hdl.handle.net/1765/40533