Higher-order aberrations after corneal collagen crosslinking for keratoconus and corneal ectasia

Greenstein, Steven A.; Fry, K. L.; Hersh, Matthew J.; Hersh, Peter S.

doi:10.1016/j.jcrs.2011.08.041

Cited by 116 publications

(104 citation statements)

References 32 publications

(29 reference statements)

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“…According to the literature, there are conflicting data on the repeatability of Pentacam in the measurement of aberrations. 34 One of the most important disadvantage of our study and aforementioned studies in which comparing the efficacy of corneal CXL according to age group is that did not compare the depth of the demarcation line with anterior segment optic coherence tomography (AS-OCT). It is known, one of the most important parameters used to compared efficacy of corneal CXL in recent years is the depth of the demarcation line created in the stroma after corneal CXL The stromal penetration of riboflavin solution may vary depending on age group, because it is known that there are significant structural changes in the cornea with age.…”

Section: Discussionmentioning

confidence: 93%

Accelerated Corneal Crosslinking Results with Respect to Age Groups

Koç¹,

Uzel²,

Koban³

et al. 2018

Turkiye Klinikleri J Ophthalmol

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Section: Discussionmentioning

confidence: 93%

Accelerated Corneal Crosslinking Results with Respect to Age Groups

Koç¹,

Uzel²,

Koban³

et al. 2018

Turkiye Klinikleri J Ophthalmol

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“…Second, aberrations were assessed using a Pentacam and not an aberrometer. However, analyses of the repeatability of the Pentacam for the measurement of aberrations have yielded conflicting data (17) . Third, because of the low number of patients, we were unable to evaluate whether the patients abided by the astigmatism rule, and could not investigate correlations with surgical results or the effects of posterior surface astigmatism.…”

Section: Discussionmentioning

confidence: 99%

Effect of corneal biomechanical properties on surgically-induced astigmatism and higher-order aberrations after cataract surgery

Koç¹,

İlhan²,

Koban³

et al. 2016

Arquivos Brasileiros De Oftalmologia

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“…43 A reduction of the corneal and ocular high order aberrations was also observed after CXL, suggesting an improvement in corneal shape. 44 The amplitude and the delayed onset response of topographical improvements strongly suggests that the improvements in keratometric readings and visual quality reported after CXL may be due to healing mechanisms as described below.…”

Section: 39-42mentioning

confidence: 97%

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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Higher-order aberrations after corneal collagen crosslinking for keratoconus and corneal ectasia

Abstract: Corneal and ocular HOAs decreased after CXL, suggesting an improvement in corneal shape.

Cited by 116 publications

References 32 publications

Accelerated Corneal Crosslinking Results with Respect to Age Groups

Accelerated Corneal Crosslinking Results with Respect to Age Groups

Effect of corneal biomechanical properties on surgically-induced astigmatism and higher-order aberrations after cataract surgery

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

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