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Advantages of customising CXL

Corneal cross-linking gets personal with topographic guidance

Dermot McGrath

Posted: Friday, December 7, 2018


François Malecaze MD, PhD

Customised or topography-guided CXL, also known as CuRV (Customised Remodeled Vision), may offer keratoconus patients a new option in personalised CXL with the potential for improvements in visual outcomes, according to François Malecaze MD, PhD.

“The goal is to selectively cross-link weaker zones on the cornea by administering customised UV patterns, and this approach holds the promise of further optimisation in the future,” Dr Malecaze told delegates at a joint ESCRS/EuCornea symposium on “Corneal Cross-Linking: Current Status and Future Perspectives” in Vienna.

There are two main theoretical advantages of CuRV, noted Dr Malecaze.

“Biomechanical analyses of keratoconic corneas using Brillouin microscopy have shown that weakening is concentrated within the area of the cone. A customised treatment, therefore, should induce a local stiffening, flatten the cone and consequently, improve visual function,” he said.

To administer the TG-CXL treatment, the epithelium is removed mechanically over the region designated for UV-A treatment, said Dr Malecaze. Dextran-free riboflavin 0.1% (VibeX Rapid; Avedro) is then instilled on the debrided stroma every two minutes for 10 minutes and a UV-A irradiation pattern programmed for each patient using the Mosaic System (Avedro).

“It is essentially a multifocal treatment with the maximal dose delivered at the apex of the cone,” said Dr Malecaze.

Summarising the clinical results of four different published studies of customised cross-linking thus far, Dr Malecaze said that best-corrected visual acuity (BCVA) showed a significant improvement of one-to-three lines of visual acuity (LogMAR) after treatment in two studies and a trend towards improvement of one-to-two lines in the other two trials. Corneal regularisation also improved significantly by at least 1.0D and the cone flattened in all treated study groups.

Dr Malecaze noted that TG-CXL induces a greater flattening effect than conventional CXL, as well as producing a gradient in the biological response to treatment from the area of the cone to the surrounding area.

“It is also very important to note that the side-effects are the same as for conventional CXL. This means that even if maximal energy is delivered at the thinnest point, the endothelial cell count remained stable in all of the studies,” he said.

The next step will be to deliver a truly personalised treatment using epi-on CXL for better patient comfort and supplemental oxygen with Boost Goggles for more enhanced flattening effect, he said.

“It holds a lot of promise. TG-CXL is safe and efficient to treat progressive keratoconus and is currently the most adapted solution to customise treatment to each patient. Promising improvement is expected with the introduction of trans-epithelial riboflavin solution and oxygen saturation,” he said.

François Malecaze: malecaze.fr@chu-toulouse.fr