Congenital Isolated Absence of the Inferior Oblique Muscle and Compensatory Aberrant Insertion of the Inferior and Lateral Recti

Absence of various extra-ocular muscles has previously been described. However isolated absence of the inferior oblique has not yet been described. Our patient was found to have a small right esotropia and limitation of right eye abduction with an abnormal head posture. Ocular movements showed a marked adduction overshoot in elevation. Exploration of the musculature revealed an absent inferior oblique with abnormally inserted and tight inferior and lateral rectus muscles. Imaging, forced duction testing and surgical exploration is recomended in cases where the signs do not fit into a clear syndrome.