title: Comparison of corneal haze and visual outcome in primary DSAEK versus DSAEK following failed DMEK.
abstract: BACKGROUND
  Descemet membrane endothelial keratoplasty (DMEK) is being proposed as the procedure of choice in corneal endothelial disease as it achieves better visual and refractive outcomes than Descemet stripping automated endothelial keratoplasty (DSAEK). Nevertheless, primary graft failure is frequent, especially during the learning curve, and secondary back-up procedure consists on DSAEK. We aim to compare corneal haze and visual acuity of patients undergoing primary DSAEK vs. patients undergoing DSAEK as a back-up procedure after primary DMEK failure.
  
  
  METHODS
  This study is a comparative case series that included 19 eyes from 16 patients with early stages of corneal failure and limitation of daily activities after primary DSAEK or secondary DSAEK. A control group of non-operated corneas included 10 aged-matched normal eyes. The study was conducted at University Hospital Ramón y Cajal and Vissum Hospital, Madrid, Spain. Corneal densitometry readings and postoperative best-corrected visual acuity in subjects with primary and secondary DSAEK were recorded 6 months after the surgery using the Pentacam Scheimpflug system (Oculus, inc.,Wetzlar, Germany).
  
  
  RESULTS
  In primary DSAEK median densitometry values (range) were statistically significantly higher (p < 0.05) than normal subjects for the full thickness, posterior and anterior part of the paracentral cornea; and the anterior part of the central cornea. In secondary DSAEK, median densitometry values were statistically significantly higher than normal subjects at all levels of the central and paracentral cornea. In secondary DSAEK, median densitometry values (range) were statistically significantly higher than in primary DSAEK in the full-thickness, anterior part and interface of the central cornea and in the full-thickness and posterior part of the paracentral cornea. Median visual acuity between groups (p = 0.47) was statistically better for the primary DSAEK group, which also had a higher percentage of patients achieving BCVA of ≥ 20/40 and ≥ 20/25 than the secondary DSAEK group (100% vs. 62% and 60% vs. 0% respectively).
  
  
  CONCLUSIONS
  There is an increase in central corneal light scattering after secondary DSAEK performed after a failed DMEK as compared to primary DSAEK. This has a negative impact on final visual acuity that needs to be considered in each patient when starting DMEK surgery.
authors.affiliation: Cornea Unit. Ophthalmology Department, Ramón y Cajal Hospital, Madrid, Spain, arnalich@hotmail.com.
authors.forename: Francisco
authors.initials: F
authors.lastname: Arnalich-Montiel
authors.forename: José L
authors.initials: JL
authors.lastname: Hernández-Verdejo
authors.forename: Noelia
authors.initials: N
authors.lastname: Oblanca
authors.forename: Francisco J
authors.initials: FJ
authors.lastname: Muñoz-Negrete
authors.forename: Maria P
authors.initials: MP
authors.lastname: De Miguel
mesh_terms: D000328:Adult; D000368:Aged; D001768:Blister / Q000503:physiopathology / Q000601:surgery*; D003315:Cornea / Q000473:pathology; D003316:Corneal Diseases / Q000503:physiopathology / Q000601:surgery; D003318:Corneal Opacity / Q000503:physiopathology*; D003720:Densitometry; D003886:Descemet Membrane / Q000601:surgery*; D057111:Descemet Stripping Endothelial Keratoplasty; D004728:Endothelium, Corneal / Q000637:transplantation*; D005260:Female; D005642:Fuchs' Endothelial Dystrophy / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D008027:Light; D008297:Male; D008875:Middle Aged; D012086:Reoperation; D012542:Scattering, Radiation; D017211:Treatment Failure; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology*