Corneal cross linking is usually recommended for patients who have progressive keratoconus or corneal ectasia. This decision is made based on changes in vision, glasses or contact lens prescription combined with changes in corneal tomography measurements. Corneal cross linking for keratoconus may also be used in patients in combination with excimer laser treatment (Athens protocol) to help stiffen and regularise the corneal shape leading to improved vision.

Currently corneal cross linking is the only treatment that is proven to halt the progression of keratoconus. Several randomised control studies have shown that CXL stops the progression of keratoconus in around 90% of patients at 1 year after treatment with the benefit maintained at 5 years. Nearly 50% of patients for keratoconus corneal cross linking gained an improvement in corneal shape.

The most widely used treatment protocol is ‘epithelium-off rapid’ corneal cross linking which is a safe, more up-to-date adaptation of the original Dresden protocol and involves 30 minutes of UV light treatment. In the accelerated protocol treatment time is reduced to under 10 minutes.
In ‘rapid’ or ‘accelerated’ CXL, the fluence and illumination of the ultraviolet light can be altered to reduce the length of UV light exposure. Several clinical studies have shown these accelerated regimens are better tolerated, safer and just as highly effective.

It is possible to treat both eyes simultaneously on the same day. It is more common to treat one eye at a time with the second eye treated a few weeks later. It is common for there to be some discomfort in the treated eye for 2-3 days after the procedure and so some prefer to have one eye treated at a time. Everyone’s description of pain is different with some reporting minor discomfort and others significant light sensitivity and pain.

Patients are given several different eye drops after corneal cross linking treatment (antibiotic / anti-inflammatory steroid eye drops / analgesia) which are to be used over the 2-4 weeks following the procedure. It is normal to feel some discomfort / light sensitivity over the first 2-3 days, but this should gradually settle. If there is any increasing pain or worsening vision, patients are advised to contact their surgeon / LaserVision office directly or visit their local A&E department. You are advised to rest / take time off work for the first week. Reading and watching TV will not harm your eye but you may find these activities uncomfortable in the first few days following treatment. Patients will be seen in the clinic one week post treatment.

The Collagen cross-linking procedure is a safe and highly effective treatment but any treatment has potential risks and complications. The eye needs time to heal and settle, and vision may be blurred for a few weeks. About 3% of patients may lose some vision due to corneal haze, scarring, corneal shape irregularity or infection. Without CXL treatment around 20% of patients will progress to require a corneal transplant in the future (DALK or PK).