Routine Care Study Evaluating Ocular Torsion

Inclusion criteria

For the subjects without oculomotor disorder

• no diplopia in different positions of gaze;
• no oculomotor disorder during the orthoptic examination (horizontal phoria <8 prism diopter, vertical phoria <4 prism diopter);
• corrected visual acuity > 8/10 on both eyes;
• binocular vision present in Lang I test (defined by 3 elements seen or appointed);
• orbital MRI: normal oculomotor muscles (including absence of atrophy of the superior oblique muscle) and lack of intra orbital expansive process;
• brain MRI: no abnormalities in the ways of oculomotor (especially no abnormalities in posterior fossa).

For the patients with SO muscle unilateral paralysis

• clinical features compatible with unilateral paralysis of the SO muscle
• muscular body atrophy of the SO on the orbital MRI without other orbital or cerebral abnormality
• binocular vision in Lang I test

Exclusion criteria

• high refractive error (< -6 diopter or >6 diopter);
• history or current oculomotor disorder or restrictive neurological disorder (dysthyroid orbitopathy, orbital trauma, retinal detachment surgery, paralysis oculomotor palsy other than IV);
• optic nerve head abnormalities in the fundus (edema for example)
• lack of binocular vision Lang I test;
• pregnant or breastfeeding patient
• patient under legal protection
• patient opposition to participate in the study