Abstract
Abstract: :
Purpose: To assess the amount of compensatory cycloduction in response to tilting of the head in patients suffering from unilateral inferior oblique overaction, and to find out whether compensatory counter-roll of the affected eye differs from that of the non-affected eye. Methods: Using infrared video-oculography (3D-VOG, SMI), 20 patients underwent binocular eye movement recordings while performing the Bielschowsky head tilt test up to 45 deg towards each shoulder. Seven patients were recorded before eye muscle surgery. Thirteen patients examined after surgery underwent the following procedures: 5 inferior oblique recessions, 7 inferior oblique recessions combined with contralateral inferior rectus recessions, and 1 contralateral inferior rectus recession. Results: Preoperative compensatory counter-roll revealed slight but clearly visible changes of the affected eye in nearly all patients. According to the inferior oblique overaction, less counter-roll was observed in the affected eye when tilting towards the affected eye's shoulder. Increased counter-roll was shown in the affected eye when tilting towards the non-affected eye's shoulder. Among the patients recorded postoperatively, those who underwent mere inferior oblique recession revealed full equilisation of both eye's counter-roll during head tilt. Those with combined surgery showed slight impairment of counter-roll, and the patient who underwent contralateral inferior rectus recession only presented the same pattern of dysfunctional compensatory cycloduction as the patients before surgery. Conclusion: Our study demonstrates that compensatory counter-roll during Bielschowsky head tilt test is specifically affected by oblique eye muscle disorders. Although slight, the changes were constant and in accordance to the expected torsional dysfunction. It can be concluded that torsional eye movement recording, especially during head tilt, can help to evaluate the effect on cycloductional behaviour following different surgical techniques for oblique eye muscle disorders.
Keywords: 406 eye movements • 589 strabismus: diagnosis and detection • 356 clinical (human) or epidemiologic studies: systems/equipment/techniques