Current status of corneal collagen cross‐linking for keratoconus: a review

Abstract

Over the past decade, corneal collagen cross-linking has become commonplace as a treatment option for individuals with progressive keratoconus. This is based on laboratory data suggesting that cross-linking using riboflavin and ultraviolet-A irradiation increases collagen diameter and the biomechanical strength of the treated cornea. Case series and limited randomised controlled trials support these findings with data demonstrating that cross-linking slows and possibly halts the progression of keratoconus. In some patients cross-linking results in an improvement in maximum corneal curvature, visual acuity, spherical equivalent and higher-order aberrations. The number of reported complications is small. More recently, variations in the treatment protocol have been described, although they have not yet been subject to comparative studies. While the published data indicate cross-linking is effective in modifying the natural history of keratoconus, the long-term impact of this treatment is still unknown. This paper reviews the theoretical basis, pre-clinical research and clinical results of corneal collagen cross-linking in keratoconus.

Evaluation of Possible Relationship Between COL4A4 Gene Polymorphisms and Risk of Keratoconus

“…25 The cornea is a clear tissue sheltering the front of the eye. In KC, the shape of the cornea progressively alters from the normal round shape to a cone shape; then, the eye bulges out.…”

Tear Function and Ocular Surface Alterations After Accelerated Corneal Collagen Cross-Linking in Progressive Keratoconus

“…28,29 Corneal collagen cross-linking therapy has been shown to partially recover the morphology of the cornea, 3 increase the resistance of corneal collagen to enzymatic degradation, 30 and provide an improvement in corneal epithelial mosaic. 22 In summary, only metaplastic changes and a decrease in goblet cell density have been seen in conjunctival IC, probably because of the toxicity of UVA 3 months after A-CXL; however, these results do not lead to deterioration in TBUT values.…”

“…2 Therefore, to stop the instability of the structure of collagen, which is the main cause of the disease, and to further strengthen the corneal collagen structure, corneal collagen crosslinking (CXL) has emerged as the primary treatment procedure in mild and moderate cases. 3 Since the first clinical trial published in 2003, 4 the efficacy and safety of standard CXL treatment (Dresden protocol) has been emphasized in many studies. However, high-fluence or accelerated CXL (A-CXL) protocol has been raised recently because the standard procedure is time-consuming.…”

Corneal collagen cross-linking in keratoconus – long-term prospective study

“…It results in early apoptosis of keratocytes to a depth of 300 m [1]. Confocal microscopy has demonstrated stromal oedema, loss of sub-epithelial nerve plexus and mid-stromal nerve fibres and increase reflectivity in the mid-stroma [2,3].…”