title: RETINAL LAYER RESPONSE TO RANIBIZUMAB DURING TREATMENT OF DIABETIC MACULAR EDEMA: Thinner is Not Always Better.
abstract: OBJECTIVE
  To identify individual retinal layer thickness changes associated with visual acuity gain in diabetic macular edema treated with ranibizumab using layer segmentation on high-resolution optical coherence tomography scans.
  
  
  METHODS
  Retrospective observational case series. Thirty-three treatment-naive eyes with diabetic macular edema were imaged by spectral domain optical coherence tomography at monthly visits while receiving intravitreal ranibizumab treatment as needed, guided by visual acuity. Thickness changes of individual layers after 1 year were quantitatively analyzed and correlated with visual acuity gain.
  
  
  RESULTS
  The mean best-corrected visual acuity improvement at 1 year was 6.2 (SEM ± 1.5) Early Treatment Diabetic Retinopathy Study letters, and central retinal thickness decreased by 66 ± 18 μm. In the central subfield, there was a significant decrease of thickness for all layers (P < 0.05) except the outer nuclear layer. Multiple linear regression analysis revealed that thickness decrease of the inner retina was associated with better visual acuity, whereas for the outer retina the opposite was true. The best estimate of final visual acuity (R = 0.817, P < 0.001) was obtained, by including baseline visual acuity and thickness change of the inner and outer plexiform layers in the model.
  
  
  CONCLUSIONS
  Whereas thickness decrease of the inner retina was positively associated with visual acuity gain, the opposite was found for the outer retina. This might be indirect evidence for recovery of the outer retina during ranibizumab treatment.
authors.affiliation: *Department of Ophthalmology, Inselspital, Bern University Hospital and University of Bern, Switzerland; and †Department of Clinical Research, University Hospital Bern, Switzerland.
authors.forename: Andreas
authors.initials: A
authors.lastname: Ebneter
authors.forename: Sebastian
authors.initials: S
authors.lastname: Wolf
authors.forename: Jain
authors.initials: J
authors.lastname: Abhishek
authors.forename: Martin S
authors.initials: MS
authors.lastname: Zinkernagel
mesh_terms: D020533:Angiogenesis Inhibitors / Q000627:therapeutic use*; D003930:Diabetic Retinopathy / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000503:physiopathology; D005260:Female; D006801:Humans; D058449:Intravitreal Injections; D008269:Macular Edema / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D000069579:Ranibizumab / Q000627:therapeutic use*; D012160:Retina / Q000000981:diagnostic imaging / Q000503:physiopathology*; D012189:Retrospective Studies; D041623:Tomography, Optical Coherence; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors; D014792:Visual Acuity / Q000502:physiology*
chemical_list: D020533:Angiogenesis Inhibitors; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D000069579:Ranibizumab