title: Photoreceptor outer segment length: a prognostic factor for idiopathic epiretinal membrane surgery.
abstract: OBJECTIVE
  To investigate prognostic factors for visual improvement in patients undergoing vitrectomy for epiretinal membrane (ERM) using spectral domain (SD) optical coherence tomography (OCT).
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  A total of 41 eyes of 38 patients.
  
  
  METHODS
  A total of 41 eyes of 38 patients with idiopathic ERM underwent ERM resection. Ophthalmic evaluations included best-corrected visual acuity (BCVA) and OCT parameters before and 1, 3, and 6 months after surgery. Correlations between OCT parameters and BCVA were assessed at each time point. Correlations between postoperative BCVA and preoperative factors were evaluated, including age, preoperative BCVA, photoreceptor outer segment (PROS) length, central foveal thickness (CFT), outer foveal thickness (OFT), and outer nuclear layer thickness (ONLT). The factors influencing postoperative BCVA were evaluated using multiple regression analysis.
  
  
  METHODS
  The BCVA at 6 months postoperatively.
  
  
  RESULTS
  The PROS length had the most significant correlation with BCVA at each time point (baseline: P = 0.0098, r = -0.409; 1 month: P = 0.0002, r = -0.586; 3 months: P < 0.0001, r = -0.642; 6 months: P = 0.0002, r = -0.577). The PROS length 1 month postoperatively was significantly decreased compared with that preoperatively (P = 0.0325), and the PROS length at 3 months recovered to the baseline length. Preoperative BCVA and PROS length were significantly correlated with postoperative BCVA at 6 months (P = 0.0055, r = 0.439 and P = 0.0089, r = -0.414, respectively). Other parameters, including age, CFT, OFT, and ONLT, were not significantly correlated with postoperative BCVA. Multiple regression analysis showed that preoperative PROS length yielded the highest regression coefficient with postoperative BCVA (P = 0.0363, standard regression coefficient = -0.335, overall R(2) = 0.289).
  
  
  CONCLUSIONS
  Imaging of PROS length with SD-OCT was found to be a good indicator of BCVA at each time point after surgery and a predictor of postoperative BCVA in patients with idiopathic ERM. The PROS length changes after surgery may indicate surgical injury and restoration of the macular outer layer.
authors.affiliation: Department of Ophthalmology, St. Marianna University School of Medicine, Miyamae-ku, Kawasaki, Kanagawa, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Shiono
authors.forename: Jiro
authors.initials: J
authors.lastname: Kogo
authors.forename: Gerd
authors.initials: G
authors.lastname: Klose
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Takeda
authors.forename: Hiroki
authors.initials: H
authors.lastname: Ueno
authors.forename: Naoto
authors.initials: N
authors.lastname: Tokuda
authors.forename: Jun
authors.initials: J
authors.lastname: Inoue
authors.forename: Akiko
authors.initials: A
authors.lastname: Matsuzawa
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Kayama
authors.forename: Satoki
authors.initials: S
authors.lastname: Ueno
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Takagi
mesh_terms: D000368:Aged; D019773:Epiretinal Membrane / Q000473:pathology* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D011379:Prognosis; D011446:Prospective Studies; D055214:Retinal Photoreceptor Cell Outer Segment / Q000473:pathology*; D041623:Tomography, Optical Coherence / Q000379:methods*; D014821:Vitrectomy