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A randomised, prospective study to investigate the efficacy of riboflavin/ultraviolet A (370 nm) corneal collagen cross-linkage to halt the progression of keratoconus
  1. David P S O'Brart1,
  2. Elsie Chan1,
  3. Konstantinos Samaras1,
  4. Parul Patel1,
  5. Shaheen P Shah2
  1. 1Department of Ophthalmology, St Thomas' Hospital, London, UK
  2. 2International Centre for Eye Health, London School of Hygiene and Tropical Medicine, London, UK
  1. Correspondence to Mr David P S O'Brart, Department of Ophthalmology, St Thomas' Hospital, London SE1 7EH, UK; davidobrart{at}


Aims A blind, randomised, prospective, bilateral study to investigate the efficacy of riboflavin/ultraviolet A corneal collagen cross-linkage to halt the progression of keratoconus.

Methods 24 patients with early/moderate bilateral keratoconus with recent progression were recruited. One eye was randomly assigned to undergo collagen cross-linkage following epithelial removal with riboflavin 0.1% and ultraviolet A (370 nm at 3 mW/cm2). The other remained untreated as a control. The follow-up was 18 months in 22 patients.

Results At 18 months, Orbscan II 3 mm, 5 mm keratometry and simulated astigmatism and cone apex power and wave-front measurements (Keraton Scout), including root mean square, coma and pentafoil showed significant reductions from baseline in treated compared with untreated eyes (p=0.04). In treated eyes at 18 months, the best spectacle-corrected acuity improved (p=0.01), and Orbscan II-simulated keratometry (p<0.001), 3 mm keratometry (p=0.008), simulated astigmatism (p=0.007), cone apex power (p=0.002), root mean square, coma, spherical aberration, secondary astigmatism and pentafoil (p=0.05) decreased from baseline. One treated eye experienced transient recurrent corneal erosions; otherwise there were no complications attributable to the treatment.

Conclusions Corneal collagen cross-linkage appears to be an effective and safe modality to halt the progression of keratoconus. Improvements in visual and topographic parameters are seen in some eyes.

  • Keratoconus
  • cross-linkage
  • riboflavin
  • ultraviolet light
  • cornea
  • dystrophy
  • treatment surgery
  • clinical trial

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  • Competing interests None.

  • Ethics approval Ethics approval was provided by the Guy's and St Thomas' Ethic Committee.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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