title: Fixation duress in the pathogenesis of upper eyelid retraction in thyroid orbitopathy. A prospective study.
abstract: BACKGROUND
  Upper eyelid retraction in thyroid eye disease may be caused by proptosis, levator and Müller's muscle infiltration with fibrosis or individual fiber enlargement, excessive sympathetic innervation, abnormal adhesions between levator palpebrae muscle and surrounding tissues, or fixation duress. Fixation duress refers to upper eyelid retraction while fixating with an eye with inferior rectus muscle restriction due to excessive simultaneous firing of the ipsilateral superior rectus and levator palpebrae muscles.
  
  
  METHODS
  The authors prospectively examined six patients with strabismus and thyroid eye disease associated with inferior rectus restriction and upper eyelid retraction in whom the eyelid retraction was suspected clinically to be a result of fixation duress. All six patients underwent recession of both inferior recti ranging from 3 to 6.5 mm (mean, 4.5 mm) to improve the ocular motility and alignment, reduce the diplopia, and mitigate the upper eyelid retraction.
  
  
  RESULTS
  Reduction of upper eyelid retraction measured as the preoperative versus postoperative difference in corneal light reflex-upper eyelid margin measurements was achieved in all patients postoperatively, ranging from 1.5 to 5.5 mm (mean, 3.2 mm). Only one patient showed significant residual retraction to warrant consideration of upper eyelid surgery.
  
  
  CONCLUSIONS
  Fixation duress plays a significant role in upper eyelid retraction of thyroid eye disease in a subset of patients with restriction of the inferior rectus muscle. In this selected group of patients, the upper eyelid retraction may be reduced or eliminated upon proper recession of the tight inferior rectus muscle(s).
authors.affiliation: Department of Ophthalmology, University of Florida College of Medicine, Gainesville 32610-0284.
authors.forename: L M
authors.initials: LM
authors.lastname: Hamed
authors.forename: A M
authors.initials: AM
authors.lastname: Lessner
mesh_terms: D004172:Diplopia / Q000601:surgery; D005141:Eyelid Diseases / Q000209:etiology / Q000503:physiopathology* / Q000601:surgery; D005403:Fixation, Ocular / Q000502:physiology; D006111:Graves Disease / Q000150:complications* / Q000503:physiopathology; D006801:Humans; D009801:Oculomotor Muscles / Q000601:surgery; D011446:Prospective Studies; D013285:Strabismus / Q000150:complications / Q000601:surgery