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

Purpose: To compare strabismus surgery outcomes of patients who have had pr ior orbital decompression for thyroid ophthalmopathy with those of patients who have not had decompression, Methods: The records of all patients opera ted on by the author for strabismus related to thyroid ophthalmopathy were retrospectively reviewed. Results: Fifty patients were included in this stu dy. Seventeen patients had previously undergone orbital decompression, and 33 patients had not. Seventy-six percent of patients who had had orbital de compression had a good or excellent outcome compared with 91% of those who had not had orbital decompression, Patients in the orbital decompression gr oup had an average of 1.4 operations compared with 1.2 in the no-decompress ion group. The average numbers of muscles operated on were 3.1 in the decom pression 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 decompre ssed. Conclusions: Patients with thyroid ophthalmopathy who have had orbita l decompression have a lower success rate of surgery for strabismus, more f requently need correction for both horizontal and vertical deviations, and have more muscles operated on than patients who have not had orbital decomp ression. The need for orbital decompression in patients with Graves' diseas e is reflective of a worse degree of orbitopathy. In addition, ocular chang es from decompression surgery may interfere with a successful result from s trabismus surgery. (J AAPOS 2000;4:102-5).