A Novel Irradiation Technology To Eliminate Treatment Failures In Corneal Crosslinking.

The currently available corneal crosslinking treatment options are based on a free irradiation path via which the cornea is irradiated by UV-A light. This currently used irradiation technique is, however, a main source for treatment failures resulting from head-movement, eye-movement and corneal curvature. Since the cornea is curved a uniform distribution of light intensity across the cornea and therefore a defined energy transfer to the entire irradiiated area of the cornea is not possible. The purpose of this study is to present a novel UV-A irradiation technology for corneal crosslinking which eliminates all these treatment failures.

Keratoconus Treatment Centers and Univesity Hospitals in Austria.

Instead of the free irradiation path for UV-A light of the conventional crosslinking technique a closed irradiation channel which connects the device to the eye is established by the new technology. The irradiation channel is lined at its inner wall by a diffusely reflecting layer. The device moves in sync with the eye- and head movements. The UV-A light source is emiting divergent light rays which undergo multiple reflections and strike the cornea from virtually all directions. The effective intensity at the corneal surface were measured by means of a curved cornea-simulating detector for both, the conventional and the novel technique.

The measurements of the energy transfer to a curved cornea via the conventional technique is highly inhomogeneous with the intended intensity at the corneal vertex only. The effective intensity at the corneal surface declines rapidly from the corneal center to the corneal periphery. Only half of the intended intensity is available anymore at 4 mm distance from the corneal center. In contrast to the conventional technique, the novel technology using the diffusely reflecting irradiation channel is able to keep the right intended intensity across the entire cornea. Initial results of the clinical application of the new technology in eyes suffering from keratoconus are reported.

The new irradiation technology presented in this study eliminates the most important treatment failures related to the conventional crosslinking irradiation technique and provides the right intensity to every surface point across the entire cormea. Further studies are required to find out whether the new technology shows better clinical results compared to the conventional crosslinking technique.