To describe the surgical technique for endoscopic medial orbital fat decompression in type 1 (lipogenic) Graves orbitopathy and report outcomes.

Retrospective interventional case review.

We reviewed 108 patients (206 orbits) with inactive, type 1 Graves orbitopathy without diplopia, who underwent endoscopic medial orbital fat decompression solely for proptosis reduction. Following endoscopic transethmoid medial orbital wall decompression, extraconal and intraconal orbital fat was removed with a low-suction cutting instrument. All patients were followed up for at least 12 months. Surgical time, preoperative and postoperative Hertel exophthalmometry, incidence of postoperative diplopia within 30-degree visual field in the primary gaze, and other complications were analyzed.

The mean surgical time was 97.7 ± 16.7 minutes (67–136 minutes). The mean follow-up was 16.0 ± 4.2 months (12–24 months). Preoperative and postoperative proptosis values at final review were 21.1 ± 2.3 mm (17–26 mm) and 13.0 ± 0.9 mm (12–15 mm), respectively (P < .001). Median reduction in proptosis was 8.0 mm with mean of 8.2 ± 1.8 mm (4–11 mm). Symmetry to within 2 mm was achieved in 106 of 108 patients (98.1%). Twenty-five of 108 patients (23.1%) had diplopia within 30-degree visual field of the gaze, and 23 of these had complete resolution within 3 months, while the remaining 2 patients required squint surgery.

Endoscopic medial orbital fat decompression may be an effective technique for proptosis in selected patients with type 1 Graves orbitopathy and is associated with a low rate of surgically induced diplopia.