Ophthalmic surgery in dysthyroid ophthalmopathy

The major focus of this study is to evaluate the ophthalmic surgery performed to treat patients with various eye changes of dysthyroid ophthalmopathy (DO) in Japan. The medical charts of DO cases that underwent eye surgery at the Olympia Eye Hospital in 1999 were reviewed. In 1999, 898 patients underwent ophthalmologic examination at the thyroid eye clinic in our hospital, and 51 cases were excluded out of the first visiting cases because they were hyperthyroid only and not associated with ophthalmopathy. This study consists of 847 cases (151 male, 696 female), mean age of 40.9 +/- 14.7 years, age distribution of 10-84 years. Surgical therapy was used on 129 eyes of 93 cases (11%) among the 847 patients. Orbital decompression was performed on 26 eyes of 15 cases. Most Japanese patients are not associated with a strong degree of proptosis, showing on average less than 20 mm. Cases with 25 mm of proptosis were scarcely observed. Extraocular muscle surgery was performed on 84 eyes of 60 cases (bilateral 17 cases, unilateral 33 cases). Types of diplopia are as follows: upward gaze, 28 cases; outward gaze, 10 cases; downward gaze, 2 cases; and complex type, 10 cases. Concerning the pathogenesis of diplopia in DO, fibrotic change plays a dominant role, in which cicatrical adhesion to the surface of the muscle is always observed in extraocular muscle surgery. After removal of cicatrical adhesion, the forced duction is completely recovered. This explains the precise mechanism of this involvement. Eyelid surgery was used on 39 eyes of 30 cases (upper eyelid, 33 eyes; lower eyelid, 6 eyes). Eyelid surgery was indicated for treatment of various anterior eye changes including upper eyelid retraction, entropion of eyelids. Better results and few complications are considered attributable to the stabilization of orbitopathy.