Characteristics of corneal biomechanical parameters and corneal thickness measured by Corvis ST and AS-OCT in progressive keratoconus treated by accelerated corneal cross-linking.

Purpose: To explore the characteristics of corneal biomechanical parameters and corneal thickness in different corneal regions in progressive keratoconus treated by accelerated "epithelium off" cross-linking (A-CXL) surgery.

Methods: This is a retrospective study and is self-controlled before and after surgery. A total of 39 eyes of 25 patients with progressive keratoconus were recruited and treated by A-CXL. The corneal biomechanical parameters and corneal thickness were recorded at baseline, 1-month, 3-month, and 6-month after surgery. Besides, analysis of correlations was applied to explore the association between these two features.

Results: Most of the biomechanical parameters, corneal thickness of different areas, as well as visual acuity, curvature and higher-order aberrations (HOAs), showed significant changes at 1 month and 3 months after surgery. Then gradually became stable and close to baseline values at 6 months postoperative. The epithelium became thicker earlier (after 1 month). The central and inferior areas of corneal stroma and the whole cornea were significantly thinnest at 3 months, other areas were thinnest at 1 month. Only several biomechanical parameters showed positive or negative correlations with corneal thickness, including the changes of them from baseline to different time after treatment.

Conclusion: The accelerated cross-linking not only has a significant effect, especially on the corneal central, inferotemporal, and inferonasal regions, which can prevent the progression of keratoconus. But also, can maintain the integrity of the epithelium, achieve corneal biomechanical recovery and improve visual acuity, curvature and HOAs in the short term at the same time.