Abstract: Pirenoxine or 1-hydroxy-5-oxo-5H-pyrido-[3,2a]-phenoxazin-3-carboxylic acid, also called pirfenossone and already used as anti-cataract agent, in the form of a pharmaceutically acceptable salt thereof, if desired, is used for the protection of the corneal tissue in photokeratectomy interventions, as cornea photoablation using excimer laser, for both refractive and therapeutic purpose. In fact pirenoxine is able to inhibit, in the cornea, the oxidative phenomena determined by reactive oxygen species (ROS) which are produced within the tissues following the laser irradiation.