The objectives of this study are to evaluate the safety and efficacy of a treatment regimen for high myopia and myopic astigmatism: LASIK followed by crosslinking performed with the KXL Crosslinking-System and VibeX Xtra (Riboflavin Ophthalmic Solution, Avedro, USA), as compared to LASIK alone, with regards to regression of refractive outcome, as measured by manifest refraction spherical equivalent (MRSE) and keratometry.

This is a controlled study of the safety and efficacy of the KXL System and VibeX Xtra (Riboflavin Ophthalmic Solution, Avedro, USA) for performing crosslinking in eyes undergoing LASIK for high myopia or myopic astigmatism. Each subject will have bilateral LASIK performed and one eye will be randomized to undergo LASIK followed by crosslinking.

Subjects will undergo bilateral LASIK. Following randomisation one eye of each subject will be treated with VibeX Xtra (Riboflavin Ophthalmic Solution) following LASIK and will be irradiated with the KXL System at 30 mW/cm2 intensity for 90 seconds continuous UV-A light treatment for a total radiant exposure of 2.7 J /cm2.

All eyes will be assessed at 1 day, 1, 3, 6, and 12 months after treatment.

Inclusion Criteria:

• eligible for bilateral myopic fs-LASIK with -6.00 to -12.00 D (diopters) with a maximum of 5.00 D astigmatism
• age > 18 years
• provided written informed consent
• difference between the MRSE and cycloplegic SE less than 0.75 D
• MRSE needed to be stable for the last 12 months (<0.5 D).

Exclusion Criteria:

• prior corneal surgery,
• forme fruste or manifest keratoconus,
• history of corneal scarring, melting, ulceration
• repeating inflammations of the eye
• taking vitamin C 1 week prior to the treatment