title: A rationale for membrane peeling in the repair of stage 4 macular holes.
abstract: OBJECTIVE
  To examine the histological and immunocytochemical characteristics of epiretinal membranes (ERM) associated with stage 4 macular holes (MH) so as to establish a vitreoretinal rationale for surgery in stage 4 MH.
  
  
  METHODS
  Consecutive patients with stage 4 MH undergoing vitrectomy and membrane peeling were recruited. Preoperatively, the eyes were examined for ERM formation over the macula and completeness of posterior hyaloid membrane (PHM) separation from the retina. ERM peel specimens obtained during surgery were sent for histological and immunocytochemical studies and were compared with the PHM specimens taken from a previous post-mortem study of eyes with physiological posterior vitreous detachment but without macular holes.
  
  
  RESULTS
  A total of 13 patients with stage 4 MH fulfilled the inclusion criteria and were recruited. Preoperatively, all eyes had an ERM over the macula and incomplete separation of the PHM seen as a defect in the PHM on specular biomicroscopy. Histologically, the ERM specimens had very similar morphological characteristics to PHM, consisting of an eosinophilic membrane of varying thickness with scattered spindle-shaped cells. The membranes stained positively for type IV collagen while the cells were glial fibrillary acidic protein positive. Postoperatively, successful closure of MH was achieved in all cases.
  
  
  CONCLUSIONS
  Stage 4 MH is characterised by incomplete separation of the PHM from the retina with remnants overlying the macula manifesting as ERM. Removal of the ERM is required during vitrectomy in order to relieve the tangential forces involved in the development of MH.
authors.affiliation: Vitreoretinal Service, Addenbrooke's NHS Trust, Hills Road, Cambridge, UK.
authors.forename: A
authors.initials: A
authors.lastname: Ang
authors.forename: D R J
authors.initials: DR
authors.lastname: Snead
authors.forename: S
authors.initials: S
authors.lastname: James
authors.forename: Y C
authors.initials: YC
authors.lastname: Yeo
authors.forename: K
authors.initials: K
authors.lastname: Satchi
authors.forename: A H C
authors.initials: AH
authors.lastname: Morris
authors.forename: A V
authors.initials: AV
authors.lastname: Poulson
authors.forename: J D
authors.initials: JD
authors.lastname: Scott
authors.forename: M P
authors.initials: MP
authors.lastname: Snead
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003094:Collagen / Q000378:metabolism; D019773:Epiretinal Membrane / Q000378:metabolism / Q000473:pathology / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D012167:Retinal Perforations / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D013048:Specimen Handling; D016896:Treatment Outcome; D014792:Visual Acuity; D014821:Vitrectomy / Q000379:methods
chemical_list: D005904:Glial Fibrillary Acidic Protein; D003094:Collagen