Laser ablation is a process of controlled removal of corneal tissue using an excimer laser beam emitting ultraviolet radiation with a wavelength of 193 nm. The mechanism of action is photoablation, i.e. breaking molecular bonds in corneal tissue by absorbing photon energy, which leads to precise vaporisation of tissue layers without thermal damage to adjacent structures. The excimer laser removes tissue with a precision of fractions of a micrometre, allowing a controlled change in the curvature and optical power of the cornea to be carried out according to the programmed ablation profile.
Laser ablation forms the basis of refractive vision correction procedures, such as LASIK, PRK, LASEK and TransPRK, used in the treatment of myopia, hyperopia and astigmatism. The depth of ablation depends on the severity of the refractive error being corrected – the greater the error, the more corneal tissue must be removed, which requires maintaining an adequate thickness of the remaining corneal stroma to ensure its biomechanical stability. Modern laser systems utilise eye-tracking and wavefront-guided or topography-guided ablation, which allows for personalised corrections that take into account the patient’s individual higher-order optical aberrations and corneal topography.