METHOD OF SURGICAL CORRECTION OF MYOPIC ASTIGMATISM Russian patent published in 2009 - IPC A61F9/01 B82B3/00 

FIELD: medicine.

SUBSTANCE: invention relates to field of medicine, namely to ophthalmic surgery. Cornea is exposed to pulse radiation of non-scanning excimer laser with Gauss radial space distribution of energy density in transverse section of ray in mode of layer-by-layer ablation. Exposure is performed by successive reduction of energy density amplitude in the centre of pulse symmetry within the interval from 175 mJ/sq cm to 100 mJ/sq cm in each successive pulse series. Parametre of mean square deviation of energy density distribution in each of next pulse series is within the interval from 2.7 mm to 1.8 mm and is preserved constant during all time of pulse series production. Within each pulse series value of energy density amplitude in the centre of pulse symmetry is constant. Each pulse series forms concave with respect to initial cornea surface ellipsoidal surfaces located on one axis, and zone of exposure is symmetrical relative to optic centre of cornea symmetry. First position of weak axis of astigmatism is determined, and large axis of formed ellipsoidal surfaces is superimposed with it, then first concave surface is formed. Ratio of length of large axis of concave ellipsoidal surface to cornea diametre is within the interval from 0.6 to 0.8. Then second ellipsoidal surface is formed, ratio of length of large axis of second ellipsoidal surface to length of large axis of first ellipsoidal surface being within the interval from 0.8 to 0.95. After that third ellipsoidal surface is formed, ratio of length of large axis of third ellipsoidal surface to length of large axis of second ellipsoidal surface being within the interval from 0.8 to 0.95. Exposure of cornea surface is carried out to radiation of excimer laser with wave length 193-250 nm, diametre of laser exposure zone from 5 to 9 mm, pulse duration 15-30 ns, pulse repetition rate from 5 to 15 HZ.

EFFECT: method ensures reduction of eye tissue trauma with simultaneous reduction of post-operation complications and volume of ablated eye tissues.

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