DIAGNOSIS AND SURGICAL-MANAGEMENT OF STRABISMUS ASSOCIATED WITH THYROID-RELATED ORBITOPATHY

Background: In the healing phase of thyroid-related orbitopathy, fibro sis and contracture of the extraocular muscles may result in restricti ve ocular motility. Ocular misalignment may occur in both eyes and alo ng three different axes of rotation, Successful surgical treatment dep ends on precise identification of the muscles that are restricting mot ility and producing the misalignment. Methods: Between 1980 and 1994, 22 patients were surgically treated for restrictive strabismus caused by thyroid-related orbitopathy. Preoperatively, all patients underwent complete neuroophthalmic, oculoplastic, and orthoptic examinations, A nalysis of ductions, measurement of torsion, and the use of monocular neutralization techniques were essential additions to the usual motili ty exam. Patients were placed into diagnostic categories based on the clinical pattern of extraocular muscle restriction, Adjustable recessi ons were done for all initial surgeries. Results: Patients with unilat eral inferior rectus involvement or with ipsilateral inferior rectus-c ontralateral superior rectus involvement had large vertical deviations (equal to or >20 prism diopters [Delta]). Patients with bilateral inf erior rectus involvement had small vertical deviations (<20 Delta). Ex cyclotorsion correlated strongly with the presence of tight inferior r ecti, Vertical comitance (upgaze versus downgaze measurement of equal to or <15 Delta) correlated with the ipsilateral inferior rectus-contr alateral superior rectus pattern of involvement. Vertical incomitance (upgaze versus downgaze measurement of >15 Delta) correlated with unil ateral inferior rectus involvement. Eighteen of 22 patients had excell ent postoperative alignment and elimination of diplopia in functional positions of gaze, Those with less favorable results developed reversa l of the hypertropia and exotropia in downgaze. Sixteen out of 19 pati ents who underwent inferior rectus recession had induced inferior eyel id retraction, Conclusion: Different combinations of extraocular muscl e restriction in this series of patients produced characteristic patte rns of misalignment. Appropriate, adjustable, strabismus surgery was s uccessful in restoring binocular vision in 21 out of 22 patients with a minimum of complications.