Accelerated, Pulsed Collagen Cross-Linking versus the Dresden Protocol in Keratoconus: A Case Series

Purpose: The aim of our study was to compare the depth of the demarcation line developing in the cornea after the standard Dresden protocol versus the accelerated, pulsed, epithelium-off corneal collagen cross-linking (CXL). Methods: This was a nonrandomized, retrospective case series. Patients with progressive keratoconus were treated with either the standard Dresden protocol (Group 1) or accelerated, epithelium-off CXL using the Avedro (Waltham, MA, USA) device (Group 2). The accelerated CXL protocol involved 18 min of pulsed ultraviolet-A (20 mW/cm2, 7.2 J/cm2, pulsed pro-file: 1 s on, 2 s off). The depth of the demarcation line was measured about 3 months postoperatively. Results: Fifty-nine eyes of 35 subjects were included in the analysis. Group 1 consisted of 19 eyes, and Group 2 of 40 eyes. The mean age of the participants was 22.21 years in Group 1 and 26.55 years in Group 2 (p = 0.184). The mean preoperative K value was 44.89 D in Group 1 and 45.20 D in Group 2 (p = 0.768). The depth of the demarcation line was 322.50 μm in Group 1 and 319.95 μm in Group 2 (p = 0.937). Conclusions: The demarcation line depth was not statistically significantly different between the two protocols. The significance of the demarcation line depth has not been fully clarified in the literature. Our results support the contention that these two techniques may have similar structural outcomes and efficacies in the treatment of keratoconus.

[1]  F. Malecaze,et al.  Transepithelial photorefractive intrastromal corneal crosslinking versus photorefractive keratectomy in low myopia. , 2019, Journal of cataract and refractive surgery.

[2]  M. Lombardo,et al.  Noninvasive real-time assessment of riboflavin consumption in standard and accelerated corneal crosslinking. , 2019, Journal of cataract and refractive surgery.

[3]  T. Kohnen,et al.  Comparison of Corneal Collagen Cross-Linking Protocols Measured With Scheimpflug Tomography , 2018, Cornea.

[4]  S. Pieh,et al.  Correlation between central stromal demarcation line depth and changes in K values after corneal cross-linking (CXL) , 2018, Graefe's Archive for Clinical and Experimental Ophthalmology.

[5]  Albert J. Vilella,et al.  Pulsed Light Accelerated Corneal Collagen Cross-Linking: 1-Year Results. , 2017, Cornea.

[6]  S. Jacob,et al.  In Vivo Confocal Microscopy after Corneal Collagen Crosslinking. , 2015, The ocular surface.

[7]  C. Jayadev,et al.  Current Protocols of Corneal Collagen Cross-Linking: Visual, Refractive, and Tomographic Outcomes. , 2015, American journal of ophthalmology.

[8]  M. Netto,et al.  Accelerated Corneal Collagen Cross-linking for Postoperative LASIK Ectasia: Two-Year Outcomes. , 2015, Journal of refractive surgery.

[9]  Terry Kim,et al.  Reshaping procedures for the surgical management of corneal ectasia , 2015, Journal of cataract and refractive surgery.

[10]  J. Mehta,et al.  Conventional Versus Accelerated Collagen Cross-Linking for Keratoconus , 2015, Eye & contact lens.

[11]  A. Fotouhi,et al.  Short‐term comparison of accelerated and standard methods of corneal collagen crosslinking , 2015, Journal of cataract and refractive surgery.

[12]  Y. Goldich,et al.  Accelerated (9 mW/cm2) corneal collagen crosslinking for keratoconus--a 1-year follow-up. , 2015, Cornea.

[13]  M. Jabbarvand,et al.  Evaluation of corneal changes after conventional versus accelerated corneal cross-linking: a randomized controlled trial. , 2014, Journal of refractive surgery.

[14]  R. Krueger,et al.  First Proposed Efficacy Study of High Versus Standard Irradiance and Fractionated Riboflavin/Ultraviolet A Cross-Linking With Equivalent Energy Exposure , 2014, Eye & contact lens.

[15]  M. Rechichi,et al.  Pulsed vs continuous light accelerated corneal collagen crosslinking: in vivo qualitative investigation by confocal microscopy and corneal OCT , 2014, Eye.

[16]  G. Waring,et al.  High‐irradiance accelerated collagen crosslinking for the treatment of keratoconus: Six‐month results , 2014, Journal of cataract and refractive surgery.

[17]  F. Hafezi,et al.  Corneal biomechanical properties at different corneal cross-linking (CXL) irradiances. , 2014, Investigative ophthalmology & visual science.

[18]  G. Kymionis,et al.  Corneal stroma demarcation line after standard and high‐intensity collagen crosslinking determined with anterior segment optical coherence tomography , 2014, Journal of cataract and refractive surgery.

[19]  A. Kanellopoulos,et al.  Keratoconus management: long-term stability of topography-guided normalization combined with high-fluence CXL stabilization (the Athens Protocol). , 2014, Journal of refractive surgery.

[20]  G. Kymionis,et al.  Correlation of the corneal collagen cross-linking demarcation line using confocal microscopy and anterior segment optical coherence tomography in keratoconic patients. , 2014, American journal of ophthalmology.

[21]  F. Hafezi,et al.  Safety profile of high-fluence corneal collagen cross-linking for progressive keratoconus: preliminary results from a prospective cohort study. , 2013, Journal of refractive surgery.

[22]  R. McDonald,et al.  Long-term follow-up of riboflavin/ultraviolet A (370 nm) corneal collagen cross-linking to halt the progression of keratoconus , 2013, British Journal of Ophthalmology.

[23]  David Muller,et al.  Photochemical kinetics of corneal cross-linking with riboflavin. , 2012, Investigative ophthalmology & visual science.

[24]  G. Kymionis,et al.  Simultaneous topography-guided photorefractive keratectomy followed by corneal collagen cross-linking for keratoconus. , 2011, American journal of ophthalmology.

[25]  Tos T. J. M. Berendschot,et al.  Use of anterior segment optical coherence tomography to study corneal changes after collagen cross-linking. , 2009, American journal of ophthalmology.

[26]  Eberhard Spoerl,et al.  Collagen crosslinking with riboflavin and ultraviolet‐A light in keratoconus: Long‐term results , 2008, Journal of cataract and refractive surgery.

[27]  Joseph Colin,et al.  Intracorneal rings for keratoconus and keratectasia , 2007, Journal of cataract and refractive surgery.

[28]  Farhad Hafezi,et al.  Corneal Cross-Linking-Induced Stromal Demarcation Line , 2006, Cornea.

[29]  T. Seiler,et al.  Riboflavin/ultraviolet-a-induced collagen crosslinking for the treatment of keratoconus. , 2003, American journal of ophthalmology.

[30]  G. Brindley,et al.  The Bunsen‐Roscoe law for the human eye at very short durations , 1952, The Journal of physiology.