Current perspectives on corneal collagen crosslinking (CXL)

Abstract

Corneal collagen crosslinking has revolutionized the treatment of keratoconus and post-refractive corneal ectasia in the past decade. Corneal crosslinking with riboflavin and ultraviolet A is proposed to halt the progression of keratectasia. In the original "Conventional Dresden Protocol" (C-CXL), the epithelium is removed prior to the crosslinking process to facilitate better absorption of riboflavin into the corneal stroma. Studies analyzing its short- and long-term outcomes revealed that although there are inconsistencies as to the effectiveness of this technique, the advantages prevail over the disadvantages. Therefore, corneal crosslinking (CXL) is widely used in current practice to treat keratoconus. In an attempt to improve the visual and topographical outcomes of C-CXL and to minimize time-related discomfort and endothelial-related side effects, various modifications such as accelerated crosslinking and transepithelial crosslinking methods have been introduced. The comparison of outcomes of these modified techniques with C-CXL has also returned contradictory results. Hence, it is difficult to clearly identify an optimal procedure that can overcome issues associated with the CXL. This review provides an up-to-date analysis on clinical and laboratory findings of these popular crosslinking protocols used in the treatment of keratoconus. It is evident from this review that in general, these modified techniques have succeeded in minimizing the immediate complications of the C-CXL technique. However, there were contradictory viewpoints regarding their effectiveness when compared with the conventional technique. Therefore, these modified techniques need to be further investigated to arrive at an optimal treatment option for keratoconus.

Different accelerated corneal collagen cross-linking treatment modalities in progressive keratoconus

“…The conventional method of CXL has become an important treatment of keratoconus since it was introduced [2]. However, the length of the standard treatment time has led to the development of accelerated crosslinking methods [3].…”

Biomaterials from the sea: Future building blocks for biomedical applications

“…Self-assemblly of the tropocollagen molecules is responsible for maintaining the structural and biological integrity of a collagen fibril on a molecular scale. The collagen fibril contains well-defined protein binding sites for cell interactions [ 89 ].…”

Corneal refractive surgery combined with simultaneous corneal cross‐linking: Indications, protocols and clinical outcomes—A review

“…7,[10][11][12][13] In some cases, this could result in corneal ectasia and loss of vision. [19][20][21][22] The surgery is expected to slow down or stop the progression of corneal ectasia. CXL involves photopolymerization of corneal collagen by the combined action of a photosensitizing substance (riboflavin) and ultraviolet-A (UVA) light.…”

“…CXL involves photopolymerization of corneal collagen by the combined action of a photosensitizing substance (riboflavin) and ultraviolet-A (UVA) light. [19][20][21][22] The surgery is expected to slow down or stop the progression of corneal ectasia. Photopolymerization increases the rigidity of the cornea and its resistance to deformation.…”