When it comes to management of keratoconus, corneal collagen crosslinking (CXL) is a minimally invasive procedure that can strengthen the cornea to halt its progression.
Seattle-When it comes to management of keratoconus, corneal collagen crosslinking (CXL) is a minimally invasive procedure that can strengthen the cornea to halt its progression.
Susan J. Gromacki, OD, MS, FAAO, and Andrew Morgenstern, OD, both from Washington Eye Physicians and Surgeons in Washington DC, discussed the indications and patient management for this procedure at an education session held at the annual meeting of the American Academy of Optometrists
Drs. Gromacki and Morgenstern have co-managed about 1,500 cases. Though the procedure has been approved in the European Union and other nations, it is not yet in the United States. It remains unknown when it will be approved.
“It is the only procedure that can strengthen the cornea to stop keratoconus progression, protecting vision and delaying or potentially eliminating the need for a corneal transplant,” Dr. Morgenstern said.
CXL works by increasing the cornea’s collagen connections (cross-links), thus helping the cornea retain its shape.
Early identification and treatment is key to keeping it from progressing, he explained.
“It is really a race against time to get it approved here,” he said.
The collagen in the cornea has links between the layers, and ultraviolet light (UV) stimulates strengthening between the bonds, which would take decades to occur naturally. The UV light is activated by riboflavin to stimulate the creation of more cross links.
Not every patient is a candidate, Dr. Gromacki said.
“It is contraindicated in children under the age of 8, although children are being treated in Europe,” she said.
Other contraindications are corneal thickness <300 to 350 µm, pregnancy or nursing, severe central corneal opacities, severe dry eye, prior herpetic infection, and patients with poor wound healing.
The technique for CXL is relatively uncomplicated:
Epi-on or Epi-off? The Dresden technique, or "epi-off" crosslinking, is initial removal of the central 9 mm of epithelium, followed by 30 minutes of riboflavin administration.
A newer and alternative procedure, transepithelial crosslinking or "epi-on" crosslinking, does not remove any epithelium. Less riboflavin is needed with epi-off techniques and there is a shorter “load time” but a higher risk of infection and haze.
Epi-on crosslinking has several distinct advantages: faster visual recovery, reduced pain, and lower risks for delayed epithelial healing, infection, and visually significant corneal haze.