Collagen Crosslinking for Keratoconus - a Randomized Controlled Clinical Trial

Inclusion Criteria: * Keratoconus diagnosis determined clinically and topographically (KISA%- index) * Significant progression is defined as change (increase) of Kmax by at least 1D from baseline at 6 months and/or change (increase) of Sim-K-ast by at least 1D from baseline at 6 months. Kmax is defined as the steepest radius of curvature (either the maximum simulated K-reading or the maximum K-reading in the 3-mm zone or the 5-mm zone) of the anterior corneal surface that progressed the most during 6 months observation * Ability to stop contact lens (rigid and soft) wear at least two weeks prior to next exam * Signed written informed consent Exclusion Criteria: * Age \< 18 years * Pregnancy * Breast feeding * History of corneal surgery * History of ocular herpes simplex infection * Minimal corneal thickness \< 300 micrometers * Recurrent corneal erosions * Other corneal (e g endothelial) or conjunktival diseases * Neurodermatitis * Severe forms av atopic disease * Collagenoses, autoimmune or other systemic disease * Systemic treatment with high doses of steroids * Severe scarring och striae of the cornea Relative exclusion criteria: * Kmax \> 58D * Minimal corneal thickness \< 400 micrometers (a modified CXL-treatment will be used swelling the cornea before UV-illumination treatment).