WHETHER or not torsion of the eye occurs on oblique gaze has been a subject of controversy for some time. Some have held for instance, that, on upward and outward gaze the eye intorts1; some, that it extorts,2 and some, that it does neither.3 The group who have claimed that torsion occurs are divided into those who speak of true torsion and those who say that only apparent (false) torsion exists.
The methods used for determining the amount of torsion have been based on the study of after-images and models, mathematical analysis and speculation. It seems that the question is subject to direct experimental approach.
It is difficult to estimate torsional movements unless one observes in the vertical plane containing the visual axis of the eye under investigation (fig. 1).
—After instillation anesthesia, and while the subject gazes ahead, ink marks are made at
MOSES RA. TORSION OF THE EYE ON OBLIQUE GAZE. Arch Ophthalmol. 1950;44(1):136-139. doi:10.1001/archopht.1950.00910020139009