Effect of prior orbital decompression on outcome of strabismus surgery in patients with thyroid ophthalmopathy

To compare strabismus surgery outcomes of patients who have had prior orbital decompression for thyroid ophthalmopathy with those of patients who have not had decompression.

The records of all patients operated on by the author for strabismus related to thyroid ophthalmopathy were retrospectively reviewed.

Fifty patients were included in this study. Seventeen patients had previously undergone orbital decompression, and 33 patients had not. Seventy-six percent of patients who had had orbital decompression had a good or excellent outcome compared with 91% of those who had not had orbital decompression. Patients in the orbital decompression group had an average of 1.4 operations compared with 1.2 in the no-decompression group. The average numbers of muscles operated on were 3.1 in the decompression group and 1.9 in the no-decompression group. Patients who had been decompressed were more than 4 times as likely to require surgery for both a horizontal and vertical deviation than patients who had not been decompressed.

Patients with thyroid ophthalmopathy who have had orbital decompression have a lower success rate of surgery for strabismus, more frequently need correction for both horizontal and vertical deviations, and have more muscles operated on than patients who have not had orbital decompression. The need for orbital decompression in patients with Graves' disease is reflective of a worse degree of orbitopathy. In addition, ocular changes from decompression surgery may interfere with a successful result from strabismus surgery.