title: Cosmetic orbital inferomedial decompression:  quantifying the risk of diplopia associated with extraocular muscle dimensions.
abstract: OBJECTIVE
  To quantify the risk of new diplopia in inferomedial orbital decompression performed for cosmetic reasons.
  
  
  METHODS
  Retrospective analysis of 114 patients with Graves orbitopathy who underwent an inferomedial orbital decompression. No patient had diplopia in any of the gaze positions or optic neuropathy. A single coronal slice 9 mm posterior to the lateral orbital rim was employed to quantify the muscular index of the extraocular recti and of the superior complex. A control group of 56 patients imaged for other reasons were also measured. After surgery the oculomotor status of all patients who complained of diplopia and of 51 patients free of diplopia was measured with the prism and cover test in the primary and secondary gaze positions.
  
  
  RESULTS
  The rate of new-onset diplopia was 14.0% (16 patients). Eye deviations were confirmed in 14 patients. Of these, 10 had significant strabismus that warranted surgical or prism treatment. Most patients had esotropia associated with small vertical deviations. The size of the medial and inferior recti was significantly associated with the development of diplopia. The estimated odds for the appearance of diplopia in patients with muscle enlargement was 12.76 (medial rectus) and 5.21 (inferior rectus). Small-angle deviations were also detected in 27.4% of patients who did not experience diplopia.
  
  
  CONCLUSIONS
  Medial and inferior recti enlargement is a strong predictor of new-onset diplopia. A large number of patients who do not report diplopia also present with small-angle deviations.
authors.affiliation: Department of Ophthalmology, Otorhinolaryngology, and Head and Neck Surgery, School of Medicine of Ribeirão Preto, University of São Paulo, Brazil.
authors.forename: Felipe
authors.initials: F
authors.lastname: Eing
authors.forename: Christine M Morello
authors.initials: CM
authors.lastname: Abbud
authors.forename: Antonio Augusto
authors.initials: AA
authors.lastname: Velasco e Cruz
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D003357:Cosmetic Techniques; D019299:Decompression, Surgical / Q000009:adverse effects*; D004172:Diplopia / Q000000981:diagnostic imaging / Q000209:etiology*; D005260:Female; D049970:Graves Ophthalmopathy / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009801:Oculomotor Muscles / Q000000981:diagnostic imaging / Q000473:pathology*; D009916:Orbital Diseases / Q000601:surgery*; D012189:Retrospective Studies; D018570:Risk Assessment; D014057:Tomography, X-Ray Computed