Primary-gaze diplopia in patients with thyroid-related orbitopathy undergoing deep lateral orbital decompression with intraconal fat debulking: a retrospective analysis of treatment outcome.

Our goal was to investigate the incidence of postoperative primary gaze diplopia in patients with thyroid-related orbitopathy (TRO) undergoing deep lateral wall orbital decompression surgery with intraconal fat debulking in the Jules Stein Eye Institute over a period of 4(1/4) years. Overall 201 orbital decompression surgeries were performed in 116 patients (23 males, 93 females). All surgeries were performed by two of the authors (R.A.G. and J.D.M.) and in the noninflammatory phase of the disease. Exophthalmos decreased by an average of 3.4 +/- 2.7 mm from 23.8 +/- 3.2 mm (17-31) to 20.4 +/- 2.5 mm (14-29), p < 0.001, 95% confidence interval (CI) (3.0:3.8). 31% of patients had preoperative primary gaze diplopia and 28.4% had postoperative primary gaze diplopia. Thirty (83%) of the 36 patients with preoperative diplopia had also postoperative diplopia; 6 (16.7%) of the 36 patients had improvement in diplopia following deep lateral wall decompression. Of the 80 (69%) of patients without preoperative double vision 3 developed postoperative double vision in primary gaze (2.6% of all patients). These 3 patients were older (56 versus 46 years, p = 0.047), had more limitation in ocular movements (p = 0.017) and achieved more decrease in proptosis with surgery (6 versus 3.1 mm, p = 0.024). No complications were associated with orbital decompression. In conclusion deep lateral wall orbital decompression surgery with intraconal fat debulking is associated with a low rate (2.6%) of new-onset primary gaze diplopia. Some patients (5.2%) with preoperative diplopia actually had improvement in diplopia postoperatively. This surgery is effective in reduction of congestion and exophthalmos, and is not associated with detrimental effects on visual acuity.