Stromal expansion enables standard epi-off CXL in thin corneas
PARIS — Stromal expansion with a donor flap obtained by femtosecond laser allows standard epithelium-off corneal cross-linking to be performed in patients with very thin corneas. This new technique, presented at EuCornea 2019 by Carlo Cagini, MD, creates an opportunity to use the Dresden protocol, so far unsurpassed in terms of efficacy, in patients who would not otherwise be eligible.
“The options so far proposed for thin corneas are safe but not as effective as the original epithelium-off procedure,” he said.
A stromal lenticule, 100 µm thick and 8.5 mm in diameter, is cut from a donor cornea using a femtosecond laser. After epithelium debridement, the lenticule is placed on the cornea and then CXL is performed in the standard manner, with instillation of 0.1% riboflavin solution every 2.5 minutes for 20 minutes and exposure to UVA radiation for 30 minutes. The lenticule is then removed, and a contact lens and medications are applied.
A study using this procedure was performed in 10 male patients with progressive keratoconus and thin corneas between 350 µm and 400 µm. The average patient age was 22 years, and patients were followed for 12 months.
“In all eyes a very nice demarcation line was visible at about 300 µm depth. Confocal microscopy showed that treatment was effective. We had no intraoperative or postoperative complications, no VA loss, no scar, no endothelial cell loss and the cornea was stable at 1 year,” Cagini said.
Provided a femtosecond laser is available, this technique is not expensive because donor corneas that are not suitable for transplantation are used. In the study, a VisuMax femtosecond laser (Carl Zeiss Meditec) was used.
“It is a good option for young patients with thin corneas suffering from progressive keratoconus in which the standard treatment cannot be performed. However, more studies are required to further establish the efficacy of this new procedure,” Cagini said. – by Michela Cimberle
Cagini C. Epi-off lenticule-on corneal collagen crosslinking in thin keratoconic corneas. Presented at: EuCornea; Sept. 13-14, 2019; Paris.
Disclosure: Cagini reports no relevant financial disclosures.