With the aim of reducing treatment time and increasing the throughput of patients, investigators are now considering the use of higher illumination intensities in the CXL procedure. In the standard CXL procedure 3 mWcm-2 is applied to a 9mm treatment zone for 30 minutes, resulting in a total energy dose of 3.4 J or a radiant exposure of 5.4 Jcm-2. However, this same level of radiant exposure can be achieved by applying a higher intensity for a shorter time and studies conducted on pig corneas have shown that increasing the illuminance intensity to 10 mWcm-2 and reducing the exposure time to 9 minutes produces a similar increase in corneal stiffness to that gained using the standard procedure [1].  The safety of using higher intensities in vivo has not yet been examined.

[1] Schumacher, S. et al. Equivalence of biomechanical changes induced by rapid and standard corneal cross-linking, using riboflavin and ultraviolet radiation. Invest Ophthalmol Vis Sci 2011; 52: 9048–9052.