Can We Measure Corneal Biomechanical Changes After Collagen Cross-Linking in Eyes With Keratoconus?-A Pilot Study

Goldich, Yakov; Barkana, Yaniv; Morad, Yair; Hartstein, Morris E.; Avni, Isaac; Zadok, David

doi:10.1097/ico.0b013e318190734d

Cited by 97 publications

(77 citation statements)

References 21 publications

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“…According to international bibliography, our study is among the few ones that attempt to investigate CH and CRF trends after CXL. Similar results were presented by Goldich et al [26] and by Sedaghat et al [27] in a series of ten and 56 eyes respectively, with a follow-up of 6 months. Vinciguerra et al [28] extended the post-operative period to 12 months; however, they recruited only 24 eyes in their report.…”

Section: Discussionsupporting

confidence: 87%

Evaluation of corneal hysteresis and corneal resistance factor after corneal cross-linking for keratoconus

Gkika

Labiris

Giarmoukakis

et al. 2011

Graefes Arch Clin Exp Ophthalmol

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Section: Discussionsupporting

confidence: 87%

Evaluation of corneal hysteresis and corneal resistance factor after corneal cross-linking for keratoconus

Gkika

Labiris

Giarmoukakis

et al. 2011

Graefes Arch Clin Exp Ophthalmol

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“…Very interesting are our findings of biomechanical corneal stability that so far has been evaluated only in patients that underwent epi off treatment [20][21][22][23][24].…”

Section: Discussionmentioning

confidence: 95%

Trans epithelial corneal collagen crosslinking for progressive keratoconus: 6 months follow up

Bernardo

Capasso

Tortori

et al. 2014

Contact Lens and Anterior Eye

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“…There were no significant differences in corneal biomechanical properties as measured with the parameters CH and CRF. 15 In another study, Sedaghat et al 16 compared CH and CRF before and after CXL for KC and concluded that although previous in vitro studies found a change in corneal rigidity, their study found no significant change in CH or CHF measured by biomechanical waveform analysis. These results were echoed in a study by Gkika et al, in which no significant change in the CRF parameters were found in keratoconic eyes before and after riboflavin/ UVA corneal CXL.…”

Section: Clinical Evaluation Of the Biomechanical Changes Occurring Imentioning

confidence: 99%

Reevaluating the Effectiveness of Corneal Collagen Cross-linking and Its True Biomechanical Effect in Human Eyes

Gatinel¹

2017

International Journal of Keratoconus and Ectatic Corneal Diseases

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The induction of cross-links in corneal tissue appears to be a promising technique to increase its stiffness and this has been the basis of treatment of keratoconus (KC) and corneal ectatic disease. However, there exists a striking discrepancy between the reported biomechanical effects of corneal collagen cross-linking (CXL) in vitro compared to in vivo, and this has not received much attention in the literature. Despite the documentation of an increase in corneal stiffness in vitro by many investigators, reports that provide evidence of measurable and consistent biomechanical changes in corneal rigidity in vivo after CXL are lacking. Indeed, the absence of documented in vivo biomechanical improvement in CXL-treated corneas is a conundrum, which needs to be further explored. To explain this discrepancy, it has been postulated that biomechanical changes induced by CXL are too subtle to be measured by currently available diagnostic tools or have characteristics not discernible by these technologies. However, the dynamic bidirectional applanation device (Ocular Response Analyzer) and dynamic Scheimpflug analyzer instruments (Corvis ST) have demonstrated the ability to quantify even subtle biomechanical differences in untreated KC corneas of different ectatic degree, and document the reduction in corneal hysteresis (CH) and corneal resistance factor (CRF) in situations where the corneal stiffness is reduced, such as after laser in situ keratomileusis and surface ablation procedures. It has also been possible to demonstrate an altered CH and CRF in patients with diabetes, smoking habit, glaucoma, Fuchs’ dystrophy, and corneal edema. It is puzzling that these diagnostic tools could document subtle biomechanical changes in these situations, yet fail to measure the purported changes induced by CXL on corneas with progressive KC. This failure to document significant and consistent biomechanical changes in corneal rigidity could suggest that CXL does not induce a simple reversal of the particular biomechanical deficits that characterize KC, or make the cornea significantly more resistant to bending forces as has been widely postulated. The absence of measurable biomechanical change in living KC corneas after CXL could be a consequence of biomechanical strengthening which is insignificant compared to the marked weakening caused by preexisting alteration of the collagen structure, disorganization of collagen fiber intertwining, and compromised structural–mechanical homogeneity that are hallmarks of keratoconic disease, especially in corneas with progressive KC. The changes in the cornea induced by CXL that have been described in vivo may instead be driven by a wound healing process in response to the removal of the corneal epithelial layer and subsequent exposure to riboflavin and ultraviolet-A (UVA). This paper will present evidence that sustains this hypothesis. How to cite this article Gatinel D. Reevaluating the Effectiveness of Corneal Collagen Cross-linking and Its True Biomechanical Effect in Human Eyes. Int J Kerat Ect Cor Dis 2017;6(1):34-41.

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Can We Measure Corneal Biomechanical Changes After Collagen Cross-Linking in Eyes With Keratoconus?-A Pilot Study

Cited by 97 publications

References 21 publications

Evaluation of corneal hysteresis and corneal resistance factor after corneal cross-linking for keratoconus

Evaluation of corneal hysteresis and corneal resistance factor after corneal cross-linking for keratoconus

Trans epithelial corneal collagen crosslinking for progressive keratoconus: 6 months follow up

Reevaluating the Effectiveness of Corneal Collagen Cross-linking and Its True Biomechanical Effect in Human Eyes

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