Theranostic Guided Riboflavin/UV-A Corneal Cross-linking

Keratoconus is a naturally-occurring ocular condition characterized by progressive thinning and steepening of the central cornea, resulting in corneal optical irregularities with increasing myopia, irregular astigmatism, corneal opacity and consequential loss of visual acuity. Riboflavin/UV-A corneal cross-linking is a procedure used to biomechanically stabilize the weak cornea in keratoconus and to slow down or halt the clinical progression of this disease. Theranostics is an emerging therapeutic paradigm that enables monitoring of image-guided therapy through the use of a theranostic module that makes use of real-time non-invasive molecular imaging analysis of the tissue being treated to achieve optimal treatment outcomes in the management of disease on a personal basis.

The theranostic software module of the C4V CHROMO4VIS™ medical device is able to measure the concentration of riboflavin into the cornea during treatment (i.e., the riboflavin score) and to provide the surgeon with an objective assessment of treatment efficacy (i.e., the theranostic score).

The scope of this study is to validate the combined use of the theranostic imaging biomarkers in predicting the flattening of corneal topography Kmax value at 1-year postoperatively. The 1-year follow-up is long enough to provide scientific evidence of the safety and efficacy of the theranostic UV-A medical device in question. A pre-operative examination ensures that every interested and willing participant fulfils the inclusion criteria of this study. Masked post-operative examinations are carried out after 1 week, 1 month, 3 months, 6 months and 12 months.

This is a multi-center clinical trial. Eligible participants are stratified with allocation ratio 1:1 into either treatment protocol (epi-off CXL and epi-on CXL) using a computer-generated stratification plan with blocks. Two different blocks are created, which include eyes with Kmax steeper or flatter than 54.0 D to allocate patients with comparable baseline Kmax values in either treatment protocol.

Inclusion criteria

criteria for inclusion in the clinical trial are those currently referred to as the golden standard for the treatment of corneal cross-linking. The criterion to determine progression of keratoconus is based on providing at least one of the following evidences:

• at least two Placido disk corneal topography measurements showing at least +1.00 D steepening of the Kmax value in the last year or longer interval period.
• at least two manifest refraction measurements showing at least -0.50 D change in spherical equivalent refraction in the last year or longer interval period.
• at least two central corneal thickness (CCT) measurements showing at least -10 µm change in in the last year or longer interval period.

Exclusion criteria

• Anterior corneal curvature steeper than 63 D;
• Corneal thickness thinner than 400 µm;
• Corneal scarring;
• Descemetocele;
• History of herpetic keratitis;
• Concomitant eye diseases;
• Inflammatory eye diseases;
• Glaucoma;
• Cataract;
• Nistagmus;
• Pregnancy;
• Breast feeding.