title: Asymmetric vitreomacular traction and symmetrical full thickness macular hole formation.
abstract: BACKGROUND
  A Full Thickness Macular Hole (FTMH) is often associated with vitreomacular traction, and this can be asymmetric with vitreomacular traction on one side of the hole but not the other. In cross-section, the elevated retinal rim around a developed FTMH is seen as a drawbridge elevation, and this drawbridge elevation may be used as a measure of morphological change. Examination of the drawbridge elevation of the retinal rim in FTMH with asymmetric vitreomacular traction may help to clarify the role of vitreomacular traction in the development of FTMH.
  
  
  METHODS
  Cases of FTMH were identified with an initial OCT scan showing vitreomacular traction on one side of the hole only and that had a follow-up OCT scan showing progression of the hole. A tangent to the retinal surface at a distance of 700 microns from the axis of the hole was used as a marker of the drawbridge elevation of the retinal rim around the macular hole. Comparisons of the drawbridge elevation and change in drawbridge elevation between the sides with and without initial vitreomacular traction were made.
  
  
  RESULTS
  There was no significant difference between the drawbridge elevation, or change in drawbridge elevation, on the side of the hole with initial vitreomacular traction compared to the side without initial traction.
  
  
  CONCLUSIONS
  There is some intrinsic mechanism within the retina to link the morphological changes on the two sides of a FTMH. A bistable hypothesis of FTMH formation and closure is postulated to explain this linkage.
authors.affiliation: Department of Ophthalmology, St James' Hospital, Leeds, UK. hong.woon@nhs.net.
authors.forename: Wai H
authors.initials: WH
authors.lastname: Woon
authors.affiliation: University of Leeds, Leeds, UK.
authors.forename: Denis
authors.initials: D
authors.lastname: Greig
authors.affiliation: University of Leeds, Leeds, UK.
authors.forename: Mike D
authors.initials: MD
authors.lastname: Savage
authors.affiliation: University of Leeds, Leeds, UK.
authors.forename: Mark C T
authors.initials: MC
authors.lastname: Wilson
authors.affiliation: University of Bradford, Bradford, UK.
authors.forename: Colin A
authors.initials: CA
authors.lastname: Grant
authors.affiliation: Department of Ophthalmology, St James' Hospital, Leeds, UK.
authors.forename: Fiona
authors.initials: F
authors.lastname: Bishop
authors.affiliation: Department of Ophthalmology, St James' Hospital, Leeds, UK.
authors.forename: Bataung
authors.initials: B
authors.lastname: Mokete
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012164:Retinal Diseases / Q000150:complications* / Q000175:diagnosis; D012167:Retinal Perforations / Q000175:diagnosis / Q000209:etiology*; D012189:Retrospective Studies; D000267:Tissue Adhesions; D041623:Tomography, Optical Coherence; D014822:Vitreous Body / Q000473:pathology*
keywords: Bistable; Full thickness macular hole; Pathogenesis; Vitreomacular traction