Clinical Ophthalmology (May 2023)

Comparison Between Pulsed and Continuous Accelerated Corneal Cross-Linking Protocols

  • Omar Yousif M,
  • Elkitkat RS,
  • Abdelsadek Alaarag N,
  • Moustafa Seleet M,
  • Hassan Soliman A

Journal volume & issue
Vol. Volume 17
pp. 1407 – 1413

Abstract

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Mohamed Omar Yousif,1,2 Rania Serag Elkitkat,1,3– 5 Noha Abdelsadek Alaarag,1 Mouamen Moustafa Seleet,1 Ashraf Hassan Soliman1 1Ophthalmology Department, Faculty of Medicine, Ain Shams University, Cairo, Egypt; 2Maadi Eye Subspecialty Center, Cairo, Egypt; 3Watany Eye Hospitals, Cairo, Egypt; 4Watany Research and Development Center, Cairo, Egypt; 5Ophthalmology Department, Faculty of Medicine, MTI University, Cairo, EgyptCorrespondence: Rania Serag Elkitkat, Email [email protected]; [email protected]: To compare between two accelerated corneal cross-linking (A-CXL) protocols in the management of keratoconus (KC) as regard to the extent of corneal treatment.Methods: This retrospective, comparative study included patients having mild to moderate, progressive KC. The study population was divided into two groups; group 1 enrolled 103 eyes of 62 patients who received pulsed light A-CXL (pl-CXL) at a power of 30 mW/cm2 with an irradiation time of 4 minutes, while group 2 comprised 87 eyes of 51 patients who received continuous light A-CXL (cl-CXL) at a power of 12 mW/cm2 with an irradiation time of 10 minutes. Recordings of the central and peripheral demarcation line depths (DD), and the maximum (DDmax) and minimum (DDmin) DD, using anterior segment optical coherence tomography, were compared between the two studied groups one month after the treatment protocol. Treatment stability was also evaluated pre and postoperatively (one year following surgery) by comparing the refractive and keratometric outcomes in both groups.Results: The differences between the preoperative corneal thickness (minimum and central) and the epithelial thickness measurements between both groups were not statistically significant. Although group 1 had slightly larger central DD (223.4 ± 62.3 um), DDmax (240.4 ± 61.8 um), and DDmin (201 ± 54 um) than those of group 2 (221.8 ± 37 um, 229.1 ± 38.4 um, and 212 ± 37.2 um, respectively), the differences between both groups’ measurements were not statistically significant. Also, the two groups showed statistically insignificant differences regarding the subjective refraction and the average and maximum keratometry pre and postoperatively, denoting visual, refractive, and keratometric stability in both groups.Conclusion: Longer duration cl-CXL seems to be as effective as pl-CXL regarding both postoperative stability and the extent of corneal tissue penetration by the ultraviolet treatment.Keywords: keratoconus, corneal cross-linking, demarcation line anterior segment OCT, pulsed light corneal cross-linking, ultraviolet A corneal cross-linking

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