Combined Keratoconus Procedures Improve Visual Function

Close-up of an eye with keratoconus, a thinning of the corneal apex that causes the center of the cornea to protrude, side view. This is a hereditary, noninflammatory degenerative corneal disease usually affecting both eyes and causing distorted vision.
Research team offers an update on the Athens protocol.

In an attempt to update the Athens protocol of managing keratoconus, investigators reviewed the method of combining 2 surgical techniques applied in the same session; corneal transepithelial photorefractive keratectomy with minimized volume ablation profile and accelerated corneal crosslinking. The participants demonstrated significant improvement in visual functioning, according to the study published in Cornea.

The pilot study looked at 25 eyes of 25 consecutive patients with keratoconus grades I, II, and III. Researchers looked at corrected and uncorrected distance visual acuities, manifest refraction, corneal curvature and higher-order aberrations, endothelial cells, and the ocular modulation transfer function preoperatively and postoperatively. The study had a minimum follow-up of 6 months. 

They found that, by approximately 8 months postoperative, mean corrected and uncorrected distance visual acuities improved significantly in patients who underwent this combination (0.07 ± 0.15 and 0.45 ± 0.39). Additionally, the spherical equivalent saw a significant decrease from baseline. 

“Meanwhile, a significant reduction was found in higher-order aberration, along with the postoperative improvement in ocular modulation transfer function,” the study explains. Corneal surface morphological parameters decreased significantly; however, no significant change was found in posterior corneal curvature or endothelial cell density between the preoperative and postoperative periods.

The study calls corneal minimized-volume ablation with accelerated crosslinking an effective and safe option for correction of mild refractive error in patients with keratoconus.

The original “Athens protocol” included combining topography-guided partial-refraction photorefractive keratectomy and CXL. “Through our research, it was recommended that the corneal minimized-volume ablation profile could be considered in the perspective ‘Athens protocol,’” according to the research team.

The limitations of the study include a lack of a control group for corneal cross-linking alone in the absence of transepithelial photorefractive keratectomy, preventing “direct comparison of treatment efficacy with the combination of customized ablation and CXL.” Longer follow-up is also needed to determine the treatment’s stability.


Yang X, Liu Q, Feng Q, Lin H. Safety and efficacy of corneal minimized-volume ablation with accelerated cross-linking in improving visual function for keratoconus. Cornea. 2020;39:1485–1492. doi:10.1097/ICO.0000000000002462.