Corneal cross-linking
Topic Status Complete
Corneal crosslinking to treat adults and children with keratoconus
Outcome of the appraisal
The evidence supports the routine adoption of corneal cross-linking (CXL) for children and adults with progressive keratoconus. Compared to standard care, CXL slows disease progression and may improve visual acuity. It may also reduce or delay the need for corneal transplantation.
Economic modelling suggests that CXL is cost effective on the basis of an assumed sustained clinical benefit for at least 14 years.
HTW recommends the acquisition of real word data to capture long-term outcomes (including patient-reported outcomes measures) in people who have CXL for keratoconus.
Why was this topic appraised?
Keratoconus is an eye condition characterised by progressive thinning and distortion of the cornea, causing a cone-shaped bulge to develop. This can lead to blurred vision, short-sightedness and sensitivity to light or glare. It typically develops in children and young adults and can deteriorate over time. If this deterioration continues and is untreated, some people with keratoconus require corneal transplantation to restore their vision. Corneal cross-linking (CXL), is a procedure that uses riboflavin eye drop medication combined with ultraviolet light treatment to stiffen and strengthen the cornea, and slow or stop progression of keratoconus.
HTW originally issued Guidance on CXL to treat keratoconus in February 2018. HTW Guidance is periodically updated when necessary. Following consultation with Optometry Wales and the UK Cross-linking Consortium, HTW agreed it was appropriate to issue updated Guidance, due to substantial changes to the evidence base since the original Guidance was issued.
Plain language summary
Keratoconus occurs when your cornea, the clear, dome-shaped front surface of your eye, thins and gradually bulges outward into a cone shape. Tiny fibres of protein in the eye, called collagen, help to hold the cornea in place. When these fibres get weak, they can’t hold their shape and the cornea gets more and more cone-like. A cone-shaped cornea can cause blurred vision, short-sightedness and sensitivity to light and glare. It typically develops in children and young adults and can deteriorate over time. Some people with keratoconus require corneal transplantation to stop them from losing their vision.
Corneal crosslinking is a treatment for people whose keratoconus is progressing rapidly and their sight loss cannot be corrected with glasses or contact lenses. In corneal cross-linking, doctors use eye drop medication and ultraviolet (UV) light to make the tissues of the cornea stronger. This process keeps the cornea from bulging more. It’s called “cross-linking” because it adds more biomechanical bonds between the collagen fibres in your eye, making them stronger.
Health Technology Wales (HTW) looked for evidence of the clinical and cost effectiveness of corneal cross linking in people with progressive keratoconus. The evidence supports the routine adoption of corneal cross-linking (CXL) for children and adults with progressive keratoconus.
Evidence Appraisal Review
EAR002-2 03.2021
Additional documents
This is an updated version of an appraisal. HTW originally issued Guidance on this topic in February 2018. The Guidance and supporting documents from previous appraisals are available from HTW upon request.
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