To evaluate clinical findings and surgical outcomes of patients with traumatic isolated inferior rectus (IR) muscle paresis.

Patients with traumatic isolated IR paresis that underwent strabismus surgery between 2011 and 2018 were included. Clinical features, type of surgery and surgical outcomes were described.

Nineteen patients with traumatic isolated IR muscle paresis were included. Fourteen patients (73.6%) were male. The mean age was 34.8±14.6 years. Left eye in 13 patients (68.4%) were involved. 13 cases (68.4%) underwent orbital reconstruction surgery for blow-out fracture. Preoperative limitation of duction in the gaze of IR muscle was -2 to -3 in all cases. Four patients (21.0%) had paradoxical contralateral (the opposite side of IR paresis) compensatory head tilt. IR muscle resection alone was the first surgical intervention in 12 (63.1%) patients. At the last follow up, 12 patients (63.1%) were orthotropic without any deviation and diplopia in primary position and down gaze. Three patients (15.7%) had residual 3 PD hypertropia in far and near without diplopia and four patients (21.0%) needed reoperation.

For traumatic isolated IR muscle paresis cases with persistent deviation at least 6 months after trauma, a stepwise approach should be used based on the size of the vertical deviation: IR resection for lower hypertropia and vertical R&R for higher hypertropia. In addition, both ipsi- and contralateral head postures can be present in these cases.