Transepithelial photorefractive intrastromal corneal crosslinking versus photorefractive keratectomy in low myopia

J Cataract Refract Surg. 2019 Apr;45(4):427-436. doi: 10.1016/j.jcrs.2018.11.008. Epub 2019 Feb 4.


Purpose: To compare the outcomes of transepithelial photorefractive intrastromal corneal crosslinking (CXL) and photorefractive keratectomy (PRK) in eyes with low myopia.

Setting: Purpan Hospital, Toulouse, France.

Design: Prospective case series.

Methods: Myopic patients with a manifest refraction spherical equivalent (MRSE) of -1.00 to -2.50 diopters (D) and a cylindrical component of plano to -0.75 D were included. The dominant eye had PRK (PRK eyes). The nondominant eye had transepithelial photorefractive intrastromal CXL with riboflavin (ParaCel Part 1 and 2), 30 mW/cm2 pulsed ultraviolet-A irradiation centered on the pupil (Mosaic System) for 16 minutes and 40 seconds, and a supplemental oxygen delivery mask (CXL eyes). The primary outcome measure was the change in the MRSE. Other outcome measures were the uncorrected (UDVA) and corrected (CDVA) distance visual acuities, mean keratometry, and endothelial cell count (ECC) over a 6-month follow-up. Adverse events were assessed.

Results: Nineteen patients were included. By 6 months, the mean MRSE had decreased by 0.72 D ± 0.42 (SD) in CXL eyes and by 1.35 ± 0.46 D in PRK eyes (P < .001). The mean change in UDVA was -0.35 ± 0.21 logarithm of the minimum angle of resolution (logMAR) in CXL eyes and -0.66 ± 0.19 logMAR in PRK eyes (P < .001). No complications were reported. The change in the ECC and CDVA was not statistically significant.

Conclusions: Photorefractive keratectomy provided better visual and refractive outcomes than transepithelial photorefractive intrastromal CXL. Transepithelial photorefractive intrastromal CXL, however, showed the potential refractive effect of CXL but with a limited magnitude of myopic correction.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Corneal Stroma
  • Corneal Topography
  • Cross-Linking Reagents / therapeutic use*
  • Epithelium, Corneal / surgery*
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Myopia / pathology
  • Myopia / therapy*
  • Photochemotherapy / methods*
  • Photorefractive Keratectomy / methods*
  • Photosensitizing Agents / therapeutic use
  • Pilot Projects
  • Prospective Studies
  • Refraction, Ocular / physiology*
  • Riboflavin / therapeutic use*
  • Visual Acuity


  • Cross-Linking Reagents
  • Photosensitizing Agents
  • Riboflavin