Twenty eyes of 15 patients with keratoconus (mean age 13±3.5 [SD] years, range 9 to 18) underwent Iontophoresis epi-on CXL

Twenty eyes of 13 patients with keratoconus (14±4 [SD] years, range 10 to 18) underwent standard epi-off CXL

Epithelium-off CXL was performed according to the Siena (Dresden modified) protocol: 2% pilocarpine was instilled 30 minutes before treatment, the epithelium was removed using a blunt knife. An isotonic solution of riboflavin 0.1% and dextran 20% was instilled for 10 minutes of corneal soaking before starting UV-A irradiation. The solution was administered every 3 minutes for a total of 30 minutes of UV-A exposure at 3mW/cm2.

The iontophoresis device was filled with a hypoosmolar riboflavin 0.1% dextran-free solution enriched with ethylenediaminetetraacetic acid and trometamol. The device was then connected to a constant current generator initially set at 0.5 mA and increased to 1.0 mA to find out the individual tolerance. Iontophoresis was then performed for 5 minutes. The corneal device was then removed before performing UVA irradiation. During the irradiation phase (10 mW/cm2 for 9 minutes), good fluorescence was clearly detectable. The total treatment time was 14 minutes.

To evaluate change of simulated maximum K (Kmax) that was calculated by a Sirius Scheimpflug camera (CSO, Firenze, Italy) by averaging the axial curvature from the fourth to the eighth Placido rings of the flattest and steepest meridians (the amplitude of the zone taken into consideration, therefore has a vari-able diameter depending on the curvature of the cornea, and the principal meridians are not nec-essarily 90 degrees away)