Resection and Transposition of the Inferior Oblique for Hypertropia due to the Inferior Rectus Loss

Purpose: To report a case of resection and transposition of the inferior oblique muscle combined with superior rectus recession as treatment for large-angle hypertropia due to unilateral loss of the inferior rectus muscle. Case summary: A 39-year-old man presented with a complaint of left hypertropia and vertical diplopia caused by blunt trauma 20 years previously. Left hypertropia of 70 prism diopters (PD) and exotropia of 16 PD in the primary gaze were noted; ocular movements of the left eye showed overactive supraduction (+4) and underactive infraduction (-5). On surgical exploration, neither the inferior rectus muscle nor capsule were present at the insertion site. The patient was diagnosed with loss of the inferior rectus muscle, thus, 7 mm of the inferior oblique muscle was resected and transposed at the original insertion site of the inferior rectus muscle; the superior rectus muscle was then recessed by 4.5 mm. After the surgery, vertical alignment was straight in the primary position, infraduction limitation was changed from -5 preoperative to -2 postoperative, and supraduction was changed from +4 preoperative to -2 postoperative. Conclusions: Extensive resection and transposition of the inferior oblique muscle combined with recession of the superior rectus may help in obtaining a successful surgical outcome in patients with inferior rectus muscle loss with a large angle of vertical deviation. J Korean Ophthalmol Soc 2019;60(8):816-819