Corneal Crosslinking Improves Visual Acuity in Early Keratoconus

Macro picture of the eye. The cornea in the form of a cone, the disease of the eye keratoconus.
Macro eye. Ophthalmic disease – keratoconus.
The procedure can have significantly different effects on vision depending on the patient’s Krumeich stage.

Corneal crosslinking (CXL) procedures significantly improve best-corrected visual acuity (BCVA) in patients with early developing keratoconus, a study published in BMC Ophthalmology reports. 

Between November 2008 and September 2018, researchers at the University Eye Hospital Tübingen followed 124 eyes of 100 participants who underwent CXL for progressive keratoconus. The traditional Krumeich scaling of keratoconus was adjusted for the study and participants were separated into groups by Kmax value (group I Kmax <48 dpt, group II Kmax 48-53 dpt, group III Kmax >53 dpt). Visual acuity, astigmatism, and tomographic parameters were measured prior to the procedure, 12 months post procedure, and 24 months post procedure.

When examining the differences in best-corrected visual acuity (BCVA) across modified Krumeich groups, researchers found significant differences in each group at 12 months (P =.014) and at 24 months (P =.032). In astigmatism, there are no significant differences between modified Krumeich groups at 12 months, but there are significant differences between groups at 24 months postoperatively (P =.023). No significant differences in tomographic parameters were found. 

CXL for the treatment of keratoconus is most effective when completed at earlier stages of disease development, according to the study. 

While the tomographic effects did not differ between groups post procedure, researchers still suggest that this procedure can have positive effects on patient outcome perspectives, especially when implemented early in disease development.   

The limitations of this study include the possibility of selection bias in the retrospective design, the short follow-up window of 24 months, which may correlate to long term effects, and the lack of consideration for confounding factors, such as age and speed of disease progression. 


Gassel CJ, Röck D, Konrad E-M, Blumenstock G, Bartz-Schmidt KU, Röck T. Impact of keratoconus stage on outcome after corneal crosslinking. BMC Ophthalmol. Published online May 6, 2022. doi:10.1186/s12886-022-02425-8