title: Factors affecting outcomes of corneal collagen crosslinking treatment.
abstract: OBJECTIVE
  To assess the effects of preoperative patient characteristics on clinical outcomes of corneal crosslinking (CXL) treatment in patients with progressive keratoconus.
  
  
  METHODS
  This retrospective study comprised 96 eyes of 96 patients who had unilateral CXL treatment for progressive keratoconus. All patients underwent a complete ophthalmological examination and corneal topography at baseline and 1 year. Subgroup analyses were performed according to the age (<30 and ≥ 30 years), gender, preoperative corrected distance visual acuity (CDVA, <0.3 and ≥ 0.3 logMAR (log of the minimum angle of resolution)), preoperative maximum keratometry (K, <54 and ≥ 54 D), baseline topographic cone location (central, paracentral, and peripheral), and preoperative thinnest pachymetry (<450 and ≥ 450 μm) to determine the associations between preoperative patient characteristics and outcomes (changes in visual acuity and maximum keratometry) of CXL treatment.
  
  
  RESULTS
  In the entire study population, mean CDVA and maximum K significantly improved after CXL treatment (P<0.001). Patients with a preoperative CDVA of 20/40 Snellen equivalent or worse (≥ 0.3 logMAR) experienced more visual improvement after CXL treatment (P<0.001). However, an age ≥ 30 years and a baseline thinnest pachymetry less than 450 μm were found significantly associated with more flattening in maximum keratometry (P=0.024, P=0.005 respectively). Gender, preoperative maximum K, and baseline topographic cone location did not show significant effect on postoperative visual acuity and maximum keratometry (P>0.05).
  
  
  CONCLUSIONS
  In patients with progressive keratoconus, age, baseline visual acuity, and baseline thinnest pachymetry seem to affect the success of the CXL treatment.
authors.affiliation: Department of Ophthalmology, Servergazi State Hospital, Denizli, Turkey.
authors.forename: I
authors.initials: I
authors.lastname: Toprak
authors.affiliation: 1] Department of Ophthalmology, Faculty of Medicine, Pamukkale University, Denizli, Turkey [2] Private Yaylalı Eye Hospital, Denizli, Turkey.
authors.forename: V
authors.initials: V
authors.lastname: Yaylalı
authors.affiliation: 1] Department of Ophthalmology, Faculty of Medicine, Pamukkale University, Denizli, Turkey [2] Private Ege Akademi Eye Hospital, Denizli, Turkey.
authors.forename: C
authors.initials: C
authors.lastname: Yildirim
mesh_terms: D000293:Adolescent; D000328:Adult; D003094:Collagen / Q000378:metabolism*; D003315:Cornea / Q000503:physiopathology*; D063171:Corneal Pachymetry; D003319:Corneal Stroma / Q000378:metabolism*; D019781:Corneal Topography; D003432:Cross-Linking Reagents / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D012189:Retrospective Studies; D012256:Riboflavin / Q000627:therapeutic use; D016896:Treatment Outcome; D014466:Ultraviolet Rays; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin