• Visual perception
• Treatment Surgery

Ocular torsion is often a most complicated problem in strabismus diagnosis and management, partly because diagnosis may be difficult under certain circumstances, and complicated because treatment options are multifarious. The perception of torsion, or tilting in one's environment, does not always accompany ocular torsion, and vice versa, thereby further obfuscating the diagnosis. In this edition of the British Journal of Ophthalmology, Parsa has added an additional, clever approach to the diagnosis of ocular torsion.1 His thorough review of the problem and new approach is worthy of a careful reading by those who manage strabismus. In the next paragraphs, I will comment on the diagnosis and management of ocular torsion, ending with some thoughts on the importance of this topic to the ophthalmologist who works with patients with ocular motility problems.

The strabismologist should be reminded that not every case of ocular torsion is caused by trochlear (4th) nerve palsies. Central nervous system aetiologies are common. Vestibular system and reticular system damage can cause torsional changes that significantly disrupt vision. Cerebellar damage, too, will also cause vague but troublesome torsional symptoms that are often intolerable to the patient.2 On the other hand, a great number of cases of central torsion are asymptomatic, even when the degree of torsion is extreme. Lateral medullary infarcts are famous for causing substantial amounts of torsion, but beyond that, estimates suggest that over 90% of acute brainstem infarcts of any type will cause torsion,3 and most of these cases are asymptomatic, diagnosed only when the patient's external visual …