Corneal Cross-Linking and Keratoconus Connection

Young adults diagnosed with keratoconus may experience progressive vision loss resulting in legal blindness. Around one in every 2,000 people has keratoconus, and this eye disorder affects men and women in equal numbers. If you are seeking treatment for keratoconus, one cutting-edge treatment available in Europe for years – corneal cross-linking – was finally approved by the Food and Drug Administration (FDA) in 2016. A particular advantage of corneal cross-linking is that it can potentially improve the cornea’s shape in a way that can make wearing contact lenses less painful (and more comfortable) for you.

Corneal cross-linking (CXL) is just one of the keratoconus treatment options offered by the Precision Keratoconus Center. The following describes how corneal cross-linking can be used in combination with contact lenses to improve vision. Additionally described are the different types of CXL procedures, and why a specific type may be preferable depending upon your circumstances.

How Corneal Cross-Linking (CXL) Affects the Cornea

Riboflavin in a solution and UVA light are utilized in this noninvasive procedure, involving only a topical anesthetic (aimed at positively impacting the collagen fibers in the cornea’s middle layer). Since these collagen fibers are the reason that corneal thinning and bulging occurs, the clinical aim of CXL is to strengthen these fibers. 

Consequent to collagen fiber strengthening, corneal stiffening (that reduces the cornea’s abnormal conical shape in keratoconus) can occur. Secondarily, corneal flattening may also occur. In this way, CXL can halt the progression of vision loss due to keratoconus – and thereby reduce the future need for a corneal transplant (or progression to legal blindness).

The two different types of CXL procedures are called “epithelium-on” and “epithelium-off” cross-linking. According to the Open Ophthalmology Journal in 2018, the “epithelium-off” Dresden protocol is the current standard CXL procedure performed in the US. The “epithelium-on” CXL procedure – requiring a longer time for riboflavin saturation of the cornea – is generally considered less effective (per an article in the Journal of Refractive Surgery in 2016).

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Side Effects of the Dresden Protocol for CXL

The aforementioned article in the Open Ophthalmology Journal also reports the following as the most common side effects or complications of the Dresden Protocol procedure for corneal surgery:

  • Experiencing post-surgical eye pain after anesthesia wears off (requiring painkillers);
  • Risk of corneal infection;
  • Risk of corneal scarring

Transepithelial Phototherapeutic Keratectomy (PTK) utilizes a laser, and may be performed instead of the Dresden Protocol for manual removal of the epithelium. Notably, the aforementioned article in the Journal of Refractive Surgery concluded that the outcomes of patients who underwent manual epithelium removal and those who underwent PTK showed no statistical difference. Overall, people with thin corneas or a history of poor wound healing are not good candidates for an “epithelium-off” CXL procedure.

A common chronic health condition specifically linked to poor wound healing is diabetes (and diabetes has been diagnosed  around 193,000 people under 20 years of age in the US). Therefore, an “epithelium-off” procedure may be contraindicated for diabetics.

Meanwhile – according to an article in the International Journal of Ophthalmology in 2018 – an emerging approach in “epithelium-on” CXL surgeries that is showing promising results is the use of iontophoresis (the introduction of ionic compounds) to increase riboflavin penetration through the epithelium.

Corneal Cross-Linking and Contact Lens Use

For keratoconus-afflicted people who experience eye pain due to corneal bulging, undergoing CXL may decrease that pain – and thereby enable these people to wear contact lenses. Furthermore, CXL in combination with contact lens use can significantly improve vision in people diagnosed with keratoconus.

The trained professionals of the Precision Keratoconus Center are available to help you to decide which type of keratoconus treatment is best for your individual circumstances.

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