Biomechanical and Histopathologic Effects of Pulsed-Light Accelerated Epithelium-On/-Off Corneal Collagen Cross-Linking

Purpose: This study aimed to compare the biomechanical and histopathologic effects of transepithelial and accelerated epithelium-off pulsed-light accelerated corneal collagen cross-linking (CXL). Methods: A total of 24 New Zealand rabbits were analyzed after sham operation (control) or transepithelial or epithelium-off operation (45 mW/cm2 for both). The transepithelial group was treated with pulsed-light ultraviolet A for 5 minutes 20 seconds, and the epithelium-off group was treated for 90 seconds. Biomechanical testing, including ultimate stress, Young modulus, and the physiological modulus, was analyzed. Histological changes were evaluated by light microscopy and transmission electron microscopy. Results: The stress–strain curve was nonlinear in both accelerated transepithelial and epithelium-off CXL groups. The stress and elastic moduli were all significantly higher in both experimental groups compared with the control group (P < 0.05), whereas there were no significant differences between the 2 treatment groups (P > 0.05). Six months after the operation, hematoxylin and eosin staining and transmission electron microscopy showed that the subcutaneous collagen fibers were arranged in a regular pattern, and the fiber density was higher in the experimental groups. Conclusions: Both transepithelial and accelerated epithelium-off CXL produced biomechanical and histopathologic improvements, which were not significantly different between the 2 pulsed-light accelerated CXL treatments.

[1]  V. Öner,et al.  Transepithelial High-Intensity Cross-Linking for the Treatment of Progressive Keratoconus: 2-year Outcomes , 2017, Current eye research.

[2]  Xing-tao Zhou,et al.  One-year Outcomes of Pachymetry and Epithelium Thicknesses after Accelerated (45 mW/cm2) Transepithelial Corneal Collagen Cross-linking for Keratoconus Patients , 2016, Scientific Reports.

[3]  Meng Li,et al.  One-Year Follow-Up of Changes in Corneal Densitometry After Accelerated (45 mW/cm2) Transepithelial Corneal Collagen Cross-Linking for Keratoconus: A Retrospective Study , 2016, Cornea.

[4]  M. Mrochen,et al.  Optimizing Corneal Cross-Linking in the Treatment of Keratoconus: A Comparison of Outcomes After Standard- and High-Intensity Protocols , 2016, Cornea.

[5]  N. Eter,et al.  Accelerated (18 mW/cm2) Corneal Collagen Cross-Linking for Progressive Keratoconus , 2015, Cornea.

[6]  D. Böhringer,et al.  Prospective, randomized, double-blind trial to investigate the efficacy and safety of corneal cross-linking to halt the progression of keratoconus , 2015, BMC Ophthalmology.

[7]  F. Raiskup,et al.  Reply: To PMID 25532633. , 2015, Journal of cataract and refractive surgery.

[8]  F. Raiskup,et al.  Corneal collagen crosslinking with riboflavin and ultraviolet‐A light in progressive keratoconus: Ten‐year results , 2015, Journal of cataract and refractive surgery.

[9]  M. Rechichi,et al.  Pulsed Light Accelerated Crosslinking versus Continuous Light Accelerated Crosslinking: One-Year Results , 2014, Journal of ophthalmology.

[10]  Matthew R. Ford,et al.  BAC-EDTA transepithelial riboflavin-UVA crosslinking has greater biomechanical stiffening effect than standard epithelium-off in rabbit corneas. , 2014, Experimental eye research.

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

[12]  Matthew R. Ford,et al.  Biological and biomechanical responses to traditional epithelium-off and transepithelial riboflavin-UVA CXL techniques in rabbits. , 2013, Journal of refractive surgery.

[13]  G. Snibson,et al.  Current status of corneal collagen cross‐linking for keratoconus: a review , 2013, Clinical & experimental optometry.

[14]  Jeremy Wernli,et al.  The efficacy of corneal cross-linking shows a sudden decrease with very high intensity UV light and short treatment time. , 2013, Investigative ophthalmology & visual science.

[15]  Y. Mandel,et al.  Clinical and Corneal Biomechanical Changes After Collagen Cross-Linking With Riboflavin and UV Irradiation in Patients With Progressive Keratoconus: Results After 2 Years of Follow-up , 2012, Cornea.

[16]  C. Mazzotta,et al.  Long-term results of riboflavin ultraviolet a corneal collagen cross-linking for keratoconus in Italy: the Siena eye cross study. , 2010, American journal of ophthalmology.

[17]  P. Vinciguerra,et al.  Intraoperative and postoperative effects of corneal collagen cross-linking on progressive keratoconus. , 2009, Archives of ophthalmology.

[18]  B. Redl,et al.  Gel Electrophoretic Analysis of Corneal Collagen After Photodynamic Cross-linking Treatment , 2008, Cornea.

[19]  Theo Seiler,et al.  Safety of UVA-Riboflavin Cross-Linking of the Cornea , 2007, Cornea.

[20]  G. Wollensak,et al.  Corneal Endothelial Cytotoxicity of Riboflavin/UVA Treatment in vitro , 2003, Ophthalmic Research.

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

[22]  D. Hoeltzel,et al.  Strip Extensiometry for Comparison of the Mechanical Response of Bovine, Rabbit, and Human Corneas , 1992 .

[23]  G. Kymionis,et al.  High-intensity (accelerated) corneal collagen cross-linking for keratoconus. , 2015, Cornea.