title: Changes in straylight and densitometry values after corneal collagen crosslinking.
abstract: OBJECTIVE
  To evaluate the change in backward-directed and forward-directed corneal straylight in eyes after corneal collagen crosslinking (CXL) and its correlation with corrected distance visual acuity (CDVA) and changes in corneal topography.
  
  
  METHODS
  Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  Following the Dresden protocol, corneal CXL was performed in eyes with progressive keratoconus. Corneal light scattering was evaluated using densitometry measurements from different corneal layers and zones obtained using Scheimpflug tomography (Pentacam HR). Retinal straylight values were measured using the C-Quant device. The CDVA was recorded during each follow-up examination. Changes in corneal topography were measured using Scheimpflug tomography.
  
  
  RESULTS
  The study evaluated 31 eyes of 31 patients. The mean densitometry of different corneal layers and in 3 different zones increased 3 months postoperatively and decreased thereafter. The mean densitometry in the 0.0 to 2.0 mm zone remained statistically significantly elevated after 12 months (P < .05). The mean preoperative retinal straylight was 1.14 log(s) ± 0.28 (SD). The mean straylight peaked after 1 month and then decreased continuously but remained elevated after 1 year at 1.26 ± 0.21 log(s). There was an increase in CDVA and flattening of the steepest keratometry (K) value (maximum K). Eyes with the greatest maximum K reduction also had the highest densitometry values.
  
  
  CONCLUSIONS
  Crosslinking-induced stromal changes resulted in an increase in densitometry, especially in the anterior stroma of the central (0.0 to 2.0 mm) zone. These changes correlated with an increase in retinal straylight but not with the postoperative CDVA values.
authors.affiliation: From the Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.
authors.forename: Niklas
authors.initials: N
authors.lastname: Pircher
authors.affiliation: From the Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.
authors.forename: Mojtaba
authors.initials: M
authors.lastname: Pachala
authors.affiliation: From the Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.
authors.forename: Franz
authors.initials: F
authors.lastname: Prager
authors.affiliation: From the Department of Ophthalmology, Medical University of Vienna, Vienna, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Pieh
authors.affiliation: From the Department of Ophthalmology, Medical University of Vienna, Vienna, Austria. Electronic address: gerald.schmidinger@meduniwien.ac.at.
authors.forename: Gerald
authors.initials: G
authors.lastname: Schmidinger
mesh_terms: D000293:Adolescent; D000328:Adult; D003094:Collagen / Q000378:metabolism*; D003315:Cornea / Q000378:metabolism / Q000503:physiopathology* / Q000528:radiation effects; D003319:Corneal Stroma / Q000378:metabolism; D019781:Corneal Topography; D003432:Cross-Linking Reagents; D003720:Densitometry; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000188:drug therapy* / Q000378:metabolism; D008027:Light; D008297:Male; D008875:Middle Aged; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use; D012160:Retina / Q000528:radiation effects; D012189:Retrospective Studies; D012256:Riboflavin / Q000627:therapeutic use; D012542:Scattering, Radiation; D014466:Ultraviolet Rays; D014786:Vision Disorders / Q000503:physiopathology*; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin