Corneal collagen cross-linking: a review

Area of Science:

• Ophthalmology
• Corneal Surgery
• Biomaterials Science

Background:

• Keratoconus and other corneal ectatic disorders are progressive conditions.
• Current treatments aim to halt progression and improve visual acuity.
• Corneal collagen cross-linking (CXL) has emerged as a promising therapeutic approach.

Purpose of the Study:

• To review the existing literature on corneal collagen cross-linking (CXL).
• To focus on high-level evidence such as seminal publications, systematic reviews, meta-analyses, and randomized controlled trials.
• To include other study designs when high-level evidence is lacking.

Main Methods:

• Literature review emphasizing seminal publications, systematic reviews, meta-analyses, and RCTs.
• Inclusion of large cohort studies, case-controlled studies, and case series with >12 months follow-up where higher-level evidence was absent.
• Analysis of data on Riboflavin/Ultraviolet A (UVA) corneal collagen cross-linking.

Main Results:

• Riboflavin/UVA CXL is the primary treatment to halt keratoconus progression, improving visual, keratometric, and topographic parameters.
• Epithelium-off CXL shows significant efficacy, while epithelium-on techniques demonstrate less effect with limited long-term data.
• The precise molecular mechanism of CXL is not fully elucidated, and current follow-up extends to 4-6 years, indicating sustained corneal stability.

Conclusions:

• Riboflavin/UVA CXL is effective in stabilizing and improving corneal ectatic disorders.
• Further research is needed to fully understand CXL's molecular mechanisms and long-term outcomes, especially for epithelium-on techniques.
• CXL shows potential in managing infectious keratitis and is being investigated for other applications.