Citation Information :
Malhotra C, Ramatchandirane B, Gupta A, Dhingra D. Transepithelial Collagen Cross-linking versus Contact Lens-assisted Collagen Cross-linking for Progressive Keratoconus with Borderline Corneal Thickness: A Prospective Comparative Study. Int J Kerat Ect Cor Dis 2018; 7 (2):96-104.
Aim: To compare outcomes of transepithelial collagen crosslinking (TECXL) and contact lens-assisted collagen crosslinking (CACXL) for progressive keratoconus with borderline corneal thickness.
Materials and methods: In this prospective, comparative, interventional series, twenty eyes with progressive keratoconus and a preoperative ‘epithelium on’ minimal corneal thickness (MCT) of 350-420 μm, were randomized to undergo TECXL (n = 11 eyes) or CACXL (n = 9 eyes) using hydroxypropyl methylcellulose (HPMC) based 0.25% and 0.1% riboflavin respectively. Primary outcomes evaluated were demarcation line depth on anterior segment optical coherence tomography (ASOCT) 1 month postoperatively: change in maximum keratometry (Kmax) and endothelial cell density (ECD) at 6 months from baseline. Postoperative pain in the first 4 days and haze at 6 months were also compared between the two techniques.
Results: Preoperative ‘epithelium on’ MCT in the TECXL (394.3 ± 12.6 μm)and CACXL (385.6 ± 13.8 μm) groups was comparable (p = 0.15); mean demarcation line depth was 74.6% (294.4 ± 57.1 μm) and 80% (308.2 ± 84.2 μm) respectively (p = 0.66). Regression (reduction of Kmax by >1 diopter) or stabilization (change in Kmax of < ± 1D) was seen in 91% (n = 10) and 89% (n = 8) eyes of the TECXL and CACXL groups, respectively. ECD at baseline and last follow up was comparable in each group (p >0.05). Postoperative pain in the first four days and haze at 6 months post the CXL procedure were also comparable (all p\'s >0.05).
Conclusion: Using HPMC riboflavin, both TECXL and CACXL had good clinical efficacy and equivalent patient comfort without compromising endothelial safety, in keratoconus patients with thin corneas.
Clinical significance: TECXL and CACXL are simple, costeffective techniques to arrest progression in keratoconus patients with borderline corneal thickness and may decrease the need for future surgical interventions like lamellar or penetrating keratoplasty.
Wollensak G, Spoerl E, Seiler T. Riboflavin/ultraviolet-Ainduced collagen crosslinking for the treatment of keratoconus. Am J Ophthalmol 2003;135(5):620-627.
Koller T, Mrochen M, Seiler T. Complication and failure rates after corneal crosslinking. J Cataract Refract Surg 2009;35(8):1358-1362.
Bottos KM, Schor P, Dreyfuss JL, et al. Effect of corneal epithelium on ultraviolet-A and riboflavin absorption. Arq Bras Oftalmol.2011;74(5):348-351.
Spoerl E, Mrochen M, Sliney D, et al. Safety of UVA-riboflavin crosslinkingof the cornea. Cornea 2007;26(4):385-389.
Hafezi F, Mrochen M, Iseli HP, et al. Collagen crosslinking with ultraviolet-A and hypoosmolar riboflavin solution in thin corneas. J Cataract Refract Surg 2009;35(4):621- 624.
Sachdev MS, Gupta D, Sachdev G, et al. Tailored stromal expansion with a refractive lenticule for crosslinking the ultrathin cornea. J Cataract Refract Surg 2015;41(5): 918-923.
Vinciguerra P, Randelman JB, Romano V, et al. Transepithelial iontophoresis corneal collagen cross linking for progressive keratoconus-initial clinical outcomes. J Refract Surg 2014; 30(11):746-753.
Leccisotti A, Islam T. Transepithelial corneal collagen crosslinking in Keratoconus. J Refract Surg 2010;26(12):942-948.
Filippello M, Stagni E, O'Brart D. Transepithelial corneal collagen crosslinking: bilateral study. J Cataract Refract Surg 2012;38(2):283-291.
Spadea L, Mencucci R. Transepithelial corneal collagen crosslinking in ultrathin Keratoconic corneas. Clinical Ophthalmology 2012;6:1785-1792.
Jacob S, Kumar DA, Agarwal A, et al. Contact Lens Assisted Collagen Cross-Linking (CACXL): A new technique for cross linking thin corneas. J Refract Surg 2014;30(6):366-372.
Wollensak G, Iomdina E. Biomechanical and histological changes after corneal crosslinking with and without epithelial debridement. J Cataract Refract Surg 2009;35(3): 540-546.
Greenstein SA, Fry KL, Bhatt J, et al. Natural history of corneal haze after collagen cross-linking for keratoconus and corneal ectasia: Scheimpflug and biomicroscopic analysis. J Cataract Refract Surg 2010;36(12):2105-2114.
Krumeich JH, Daniel J. Live epikeratophakia and deep lamellar keratoplasty for I-III stage-specific surgical treatment of keratoconus. Klin Monbl Augenheilkd 1997;211:94-100.
Wong D, Hockenberry MJ, Wilson D. Wong's Essentials of Pediatric Nursing, 8th edition. St. Louis: Mosby, 2009.
Malhotra C, Jain AK, Gupta A, et al. Demarcation line depth after contact lens–assisted corneal crosslinking for progressive keratoconus: Comparison of dextran-based and hydroxypropyl methylcellulose–based riboflavin solutions. J Cataract Refract Surg 2017;43(10):1263-1270.
Caporossi A, Mazzotta C, Paradiso AL, et al. Transepithelial corneal collagen crosslinking for progressive keratoconus:24- monthclinical results. J Cataract Refract Surg 2013;39(8):1157- 1163.
Magli A, Forte R, Tortori A, et al. Epithelium-off corneal collagen cross-linking versus transepithelial cross-linking for pediatric keratoconus. Cornea 2013;32(5):597-601.
Çerman E, Toker E, Ozcan DO. Transepithelial versus epithelium- off crosslinking in adults with progressive keratoconus. J Cataract Refract Surg 2015;41(7):1416-1425.
Rossi S, Orrico A, Santamaria C, et al. Standardversus transepithelial collagen cross-linking in keratoconus patients suitable forstandard collagen cross-linking. Clin Ophthalmol 2015;9:503-509.
Buzzonetti L, Petrocelli G. Transepithelial corneal crosslinking in pediatric patients: early results. J Refract Surg 2012;28(11):763-767.
Stojanovic A, Chen X, Jin N, et al. Safety andefficacy of epithelium-on corneal collagen cross-linking using a multifactorialapproach to achieve proper stromal riboflavin saturation. Journal of Ophthalmology 2012.
Bikbova G, Bikbov M. Transepithelial corneal collagen crosslinking by iontophoresisof riboflavin. Acta Ophthalmol 2014;92(1): e30-e34.
Waltman SR, Patrowicz TC. Effects of hydroxypropyl methylcellulose and polyvinyl alcohol on intraocular penetration of topical fluorescein in man. Invest Ophthalmol 1970; 9(12):966- 970.
Ehmke T, Seiler TG, Fischinger I, et al. Comparison of corneal riboflavin gradients using dextran and HPMC solutions. J Refract Surg 2016;32(12):798-802.
Hagem AM, Thorsrud A, Sandvik GF, et al. Collagen crosslinking with conventional and accelerated ultraviolet-A irradiation using riboflavin with hydroxypropyl methylcellulose. J Cataract Refract Surg 2017;43(4):511-517.
Wollensak G, Aurich H, Wirbelauer C, et al. Significance of the riboflavin film in corneal collagen crosslinking. J Cataract Refract Surg 2010;36(1):114-120.
Gatzioufas Z, Raiskup F, O'Brart D, et al. Transepithelial corneal cross-linking using an enhanced riboflavin solution. J Refract Surg 2016;32(6):372-377.
Muller D, Friedman M, Sherr E. Maximizing efficacy of accelerated transepithelial cross-linking. Avedro, http://www.avedro.com/white-papers.