Corneal changes in adult patients with progressive keratoconus after accelerated corneal cross-linking: prospective 6-month interim study results

Aim of the study
To assess corneal densitometry (CD) and endothelium changes in adult patients with progressive keratoconus (PKC) after accelerated corneal cross-linking (A-CXL) and compare them with healthy myopic controls.

Material and methods
12 PKC patients who underwent A-CXL between 5 August 2020 and 22 March 2021 were examined and compared with 12 healthy myopes (control group). Evaluation of visual acuity, IOP, corneal topography, densitometry and specular microscopy were performed preoperatively and at the 1st, 3rd and 6th postoperative month.

Results
In the PKC group, a significant elevation of CD values were found in the 0-2, 2-6 zones of the anterior, central and total corneal layers after each follow-up visit. In the posterior corneal layer, they were significantly higher only in the 2-6 zone at the 6th postoperative month. The mean CD values of myopic corneas was statistically significantly lower only in the 0-2 and 2-6 zones of the anterior, central and total layers compared with PKC-affected corneas 6 months after the A-CXL procedure. In the posterior corneal layer, the mean CD values of myopes were statistically significantly lower only in the 2-6 zone compared with baseline and 6-month post-A-CXL values. A statistically significant decrease of the endothelial coefficient of variation and increase of number of hexagonal cells was found 6 months after A-CXL in the PKC group compared with controls.

Conclusions
A-CXL induces changes in corneal transparency, especially in the central 6 mm zone of anterior and central corneal stromal layers. Further-more, transient morphological modifications in the corneal endothelium may occur following this procedure.