SURGICAL METHOD FOR CORRECTING AMETROPIA USING ASPHERIC ABLATION Russian patent published in 2004 - IPC

FIELD: medicine.

SUBSTANCE: method involves treating eye cornea with ultraviolet pulsating laser radiation having Gauss energy density distribution over beam cross-section. Beam diaphragm is tuned on laser radiation ablation threshold to form round spot of 0.3-1.2 mm diameter and energy of 0.7-1.4 mJ per pulse, pulse duration of 4-7 ns and pulse succession frequency from 100 to 300 Hz. Cornea treatment is concentrated in scanning grid points arranged in equilateral triangles with ablation point distribution density being greater than in peripheral part. Treatment points form flat irregular figure built with broken lines inscribed into circle in the cases of myopia correction or into ring in the cases of hypermetropia correction. The scanning grid is shifted several times. The treatment is carried out on the following scanning grid having its points between those of the previous one.

EFFECT: reduced ablation depth; enhanced effectiveness in obtaining uniform surface after treatment; shorter operation time.

3 dwg