Corneal cross linking

Corneal collagen cross linking (CXL) has been developed over the last 15 years. The procedure aims to strengthen the cornea of the eye by application of vitamin B2 (riboflavin), followed by treatment with ultraviolet A (UV-A) light.

This procedure is often recommended when the cornea needs strengthening; especially for the treatment of keratoconus, or where there is an unstable cornea.

How does corneal cross linking work?
Corneal cross linking works by increasing the number of bonds between collagen fibres. It can be performed as a staged procedure with wavefront-guided LASEK (surface excimer laser treatment). After cross linking the corneal shape can improve with a significant increase in mechanical stiffness of the cornea.

The cross linking procedure

  • Prior to treatment corneal scans are performed to measure the contour and thickness.

  • You lie down on a flat bed, and after applying topical anaesthetic drops, the corneal epithelium is partially scored using a special instrument.

  • Riboflavin drops are then applied until the cornea is yellow coloured (due to the Riboflavin).

  • Using an Avedro™ cross-linking system ultraviolet light (UVA) is applied at 365 nm wavelength, for between 8 to 30 minutes. A calibrated UVA light source is used.

  • At the end of the procedure, a medical contact lens is placed over the cornea and this is removed in the clinic after three days.

Possible complications
Mr Stevens has an excellent track record for achieving a very low complication rate with his surgery. However all procedures carry some risk.

When performed by a skilled surgeon with modern equipment, corneal cross-linking has a low risk of serious complication. Possible complications include prolonged healing of the corneal epithelium with delayed recovery of vision, corneal stromal scarring or melting and failure of the cross-linking to increase corneal strength and stability. Overall the risk to benefit ratio for cross-linking is generally considered good and cross-linking should be considered where there is weakening of the cornea and progression of warpage.

Lesser but common issues may include some degree of dry eye or blepharitis (irritation of the eyelids) in the healing period.

There is some degree of unpredictability in outcome as with any corneal surgery. You should read all the information given to you about possible complications before undergoing any treatment.

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    Riboflavin (Vitamin B2)

    Riboflavin_vitamin_b2
More about corneal cross linking

Photo therapeutic keratectomy (PTK)

Photo Therapeutic Keratectomy (PTK) is when surface excimer laser treatment is used to treat a medical corneal condition or corneal irregularity.

A PTK procedure is often used to treat loose corneal epithelium (corneal erosion, recurrent erosion syndrome), corneal scars, injury or irregularity.

Treatment technique
PTK may be an entirely manual treatment, based on the skill and experience of the surgeon. Alternatively, it may be a customised wavefront-guided or corneal topography-guided laser treatment.

Individual advice
PTK is sometimes performed as a staged series of procedures improving corneal contour and the refractive state (your vision). Since each treatment is tailored to the individual eye and condition, specific advice is given on an individual basis.

Possible complications
Mr Stevens has an excellent track record for achieving a very low complication rate with his surgery. However all procedures carry some risk.

PTK treatment can range from a simple procedure to highly complex treatment involving manual and wavefront-guided treatments, staged over time. Possible complications are then similar to surface excimer laser treatment (LASEK), but for complex PTK the main issue is unpredictability.

Lesser but common issues may include some degree of dry eye or blepharitis (irritation of the eyelids) in the healing period.

More about PTK

Corneal transplantation

As a specialist corneal surgeon, Mr Stevens performs corneal transplantation, including femtosecond laser corneal transplantion. He does this within his NHS clinic at Moorfields Eye Hospital.