Ocular Torsional Changes in Anterior Plagiocephaly

Introduction: Anterior plagiocephaly has been associated with a mechanical disadvantage to superior oblique secondary to the retrusion of trochlea. This posterior placement should theoretically strengthen the superior oblique in its torsion action both in primary and secondary position (abduction). Materials and Methods: We did an observation study to document the ocular torsional changes by measuring disc foveal angle (DFA) in fundus photograph in five patients with anterior plagiocephaly and unilateral inferior oblique overaction. All patients had right sided anterior plagiocephaly and 2 patients had an associated posterior plagiocephaly. Results: Mean DFA in right eye (affected eye) was 15.8 +/-1.9 (13 -18 degrees) and the unaffected eye was 7.6 +/- 2 (range 6-10 degrees). All the patients showed inferior oblique overaction and a V pattern. We found that the affected eye shows excyclotorsion instead of an expected incyclotorsion. This cannot be explained on the basis of retrusion of trochlea and a mechanical disadvantage to the posterior fibres (responsible for depression in adduction) of the superior oblique. Conclusions: The affected eye in anterior plagiocephaly shows excyclotorsion.