Incidence and treatment of diplopia after three-wall orbital decompression in graves' ophthalmopathy

Purpose: To describe our experience treating diplopia after orbital decompression in patients with thyroid orbitopathy. Patients and Methods: From May 1997 to July 2001, we performed orbital decompression on 102 patients (34 men and 68 women) with severe proptosis. In 10 (9.8%) of these patients who had no diplopia preoperatively, diplopia in primary gaze occurred after decompression. In 19 (18.6%) of the patients with diplopia in primary gaze before surgery, there was no modification of diplopia after decompression. In 24 (23.5%) of the patients with diplopia in primary gaze before surgery, a more severe imbalance occurred after decompression. Forty-four (83%) of these 53 patients underwent adjustable extraocular muscle surgery with the use of viscoelastic substances to gain single vision in primary position. In 9 (17%) of the patients, diplopia was resolved with the use of prismatic lenses. Results: In 31 (70.4%) of 44 patients, we obtained a stable resolution of diplopia in primary position (minimum follow-up, 6 months). In 10 (22.7%) of these patients, a second surgery on the oblique muscles was necessary 6 months after the first surgery to resolve torsional diplopia. In 3 (6.8%) of the patients, diplopia has been resolved with prismatic lenses. Conclusion: Orbital decompression reduces proptosis, but may cause diplopia or worsen it.