title: Comparative Analysis of Refractive and Topographic Changes in Early and Advanced Keratoconic Eyes Undergoing Corneal Collagen Crosslinking.
abstract: OBJECTIVE
  To compare the refractive and topographic changes at 1 year in eyes with early and advanced keratoconus undergoing corneal collagen crosslinking (CXL). A prospective, nonrandomized comparative clinical intervention study.
  
  
  METHODS
  Thirty eyes of patients with keratoconus underwent CXL. They were divided into 2 groups based on their mean central keratometry: group A [mean central K ≤ 53 diopters (D)] and group B (mean central K > 53 D). Uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), refraction, topography, pachymetry, and endothelial cell counts were evaluated at baseline and at 1, 3, 6, and 12 months of follow-up.
  
  
  RESULTS
  The mean baseline logarithm of the minimum angle of resolution (logMAR) UCVA and logMAR BCVA in group A was 1.007 ± 0.30 and 0.566 ± 0.21, respectively. The values improved to 0.727 ± 0.29 (P = 0.001) and 0.306 ± 0.15 (P = 0.001) at 1-year post CXL. The mean baseline logMAR UCVA and logMAR BCVA in group B were 1.040 ± 0.24 and 0.641 ± 0.25, respectively. It changed to 0.953 ± 0.26 (P = 0.054) and 0.633 ± 0.27 (P = 0.891) at 1 year. The improvement in the UCVA and BCVA was statistically significant in group A as compared with that in group B. The mean baseline flattest, steepest, central, and apical keratometry in group A were 48.7 ± 2.5 D, 54.9 ± 3.3 D, 49.5 ± 1.4 D, and 57.3 ± 2.3 D, respectively. At 12 months, the values changed to 47.8 ± 2.4 D, 54.1 ± 3.0 D, 48.8 ± 1.8 D, and 56.2 ± 2.7 D, the change being statistically significant for mean flat and apical K only (P < 0.05). All the 4 indices did not show any statistically significant difference at 12 months in group B (P > 0.05).
  
  
  CONCLUSIONS
  Corneal CXL is more effective in improving the refractive and topographical parameters at 1 year when it is performed early in the course of the disease.
authors: Guru Nanak Eye Centre, Maulana Azad Medical College, New Delhi, India.
authors: Ritu
authors: R
authors: Arora
authors: Parul
authors: P
authors: Jain
authors: J L
authors: JL
authors: Goyal
authors: Deepa
authors: D
authors: Gupta
mesh_terms: D000293:Adolescent; D000328:Adult; D002452:Cell Count; D002648:Child; D003094:Collagen / Q000378:metabolism*; D063171:Corneal Pachymetry; D003319:Corneal Stroma / Q000378:metabolism; D019781:Corneal Topography; D003432:Cross-Linking Reagents; D004728:Endothelium, Corneal / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007640:Keratoconus / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D011446:Prospective Studies; D012029:Refraction, Ocular / Q000502:physiology*; D012256:Riboflavin / Q000627:therapeutic use; D014466:Ultraviolet Rays; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult
chemical_list: D003432:Cross-Linking Reagents; D017319:Photosensitizing Agents; D003094:Collagen; D012256:Riboflavin