title: Corneal Densitometry and Higher Order Aberrations After Bowman Layer Transplantation: 1-Year Results.
abstract: OBJECTIVE
  To evaluate corneal densitometry and higher order aberrations (HOAs) up to 1 year after Bowman layer (BL) transplantation.
  
  
  METHODS
  This was a retrospective study carried out at a tertiary referral center. Fifteen eyes of 14 patients who underwent BL transplantation for advanced keratoconus and had at least 1 year of follow-up were examined before BL transplantation and postoperatively at 1 day, 1 week, and 1, 3, 6, and 12 months. Corrected distance visual acuity (CDVA) with spectacles and contact lenses, anterior and posterior HOAs, and corneal densitometry were analyzed.
  
  
  RESULTS
  One year after surgery, average logarithm of the minimum angle of resolution of spectacle-CDVA changed from 1.35 (±0.46) preoperatively to 0.96 (±0.32, P < 0.001), whereas average logarithm of the minimum angle of resolution of CDVA with contact lens remained stable after surgery (P = 0.126). Anterior and posterior HOA root mean square decreased from 3.08 ± 0.59 to 2.67 ± 0.71 μm and 7.32 ± 2.20 to 6.30 ± 2.18 μm, respectively (P < 0.05). Spherical aberration ((Equation is included in full-text article.)) improved on both anterior and posterior corneal surfaces (P < 0.001). After 1 year, corneal backscattering values showed an increase as compared with preoperative values mostly involving the central and posterior layers of the cornea, with a peak 1 month after surgery (P < 0.005 in zones 2-6 and 6-10 mm). No correlation between HOAs or corneal backscatter and CDVA was found.
  
  
  CONCLUSIONS
  Corneal HOAs, especially spherical aberration, decreased for both anterior and posterior corneal surfaces after BL transplantation, whereas corneal backscattering increased, mostly in the central and posterior layers, where the graft has been placed. Changes in HOAs and corneal backscattering did not correlate with CDVA.
authors.affiliation: *Netherlands Institute for Innovative Ocular Surgery, Rotterdam, the Netherlands; †Melles Cornea Clinic Rotterdam, Rotterdam, the Netherlands; and ‡Amnitrans EyeBank, Rotterdam, the Netherlands.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Luceri
authors.forename: Jack
authors.initials: J
authors.lastname: Parker
authors.forename: Isabel
authors.initials: I
authors.lastname: Dapena
authors.forename: Lamis
authors.initials: L
authors.lastname: Baydoun
authors.forename: Silke
authors.initials: S
authors.lastname: Oellerich
authors.forename: Korine
authors.initials: K
authors.lastname: van Dijk
authors.forename: Gerrit R J
authors.initials: GR
authors.lastname: Melles
mesh_terms: D057128:Aberrometry; D000293:Adolescent; D000328:Adult; D000368:Aged; D050541:Bowman Membrane / Q000601:surgery*; D003315:Cornea / Q000503:physiopathology*; D016039:Corneal Transplantation; D057108:Corneal Wavefront Aberration / Q000503:physiopathology*; D003720:Densitometry; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000503:physiopathology / Q000601:surgery*; D008027:Light; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012542:Scattering, Radiation; D014792:Visual Acuity / Q000502:physiology