Corneal Cross-Linking: Indications and Contraindications

Abstract

Cross-linking (CXL) has gained popularity not only for arresting the progression of keratoconus and corneal ectasias but also for other indications such as corneal infections, chemical burns, bullous keratopathy, and other causes of corneal edema. Besides, CXL has also been used in combination with other treatment modalities in order to improve refractive outcomes, visual acuity, and corneal topography in patients with progressive corneal ectasias. However, there are contraindications for the procedure. Until recently, corneas less than 400 μm thick were a formal contraindication for the procedure. Currently, there are variations in the technique that allow much thinner corneas to be treated, making this a relative contraindication. Other contraindications are prior herpetic ocular infection, severe dry eye, active eye disease, systemic diseases such as collagenoses, autoimmune disorders, connective tissue diseases, severe forms of atopic disease, neurodermatitis, diabetes mellitus, severe corneal scarring or opacification, neurotrophic keratopathy, past history of epithelial healing disorders, rheumatic disorders, autoimmune disorders, pregnancy or breastfeeding, and inability to provide informed consent. CXL has been shown to be a safe and effective technique to prevent the progression of keratoconus or in association with other techniques as mentioned above, but like other surgical procedures, it is not a risk-free technique. Therefore, correct indication is important, avoiding cases at increased risk for complications.