ABSTRACT
Refractive corneal surgery aims at modifying the refractive corneal power by increasing or reducing the central bending radius. The mean central bending radius in the adult population is 7.80 mm (43.2 dioptres). The refractive power of the cornea results from the sum of the powers of three optical interfaces: air-lachrymal film (+43.7 dioptre), lachrymal film-cornea (+5.3 dioptre) and cornea-aqueous humour (−5.8 dioptre). For myopia, there is no correlation between the entity of the myopia and the bending radius, for which the purpose of refractive surgery is not that of flattening an abnormally curved cornea but of flattening its central part so that the dioptric power is related to the dioptric power of the lens, to the anterior chamber depth and to the axial length to obtain the desired final refraction.
