MULTI-FOCAL INTRAOCULAR LENS AND METHOD OF MANUFACTURE OF THAT LENS Russian patent published in 2007 - IPC A61F2/14 B29D11/02 

FIELD: medicine; ophthalmology.

SUBSTANCE: multi-focal intraocular lens can be used for correction of vision and for production of multi-focal intraocular lens. Lens has two refracting surfaces; at least one lens has diffraction structure in form of microscopic relief on its surface. Diffraction structure is made in such way that central diffraction area and concentric diffraction areas are formed onto it; areas are disposed around mentioned central area. On the way of mentioned diffraction areas from center of lens to its peripheral part, square of any sequent diffraction area is (1+M) times bigger than area of previous diffraction area, where M is factor of area increment; value of factor equals at least to cλ/f, where c is dimensionless aberration coefficient, λ is structure wavelength, f is focal length of diffraction structure. Method of manufacture of multi-focal intraocular lens is based upon production of pair of matrices, which matrices when being disposed in opposition to each other, form cavity which follows preset shape of lens. Then the cavity is filled with liquid transparent matter of lens, followed by hardening. For manufacture of matrix, forming microscopic relief of diffraction structure, liquid photoresist material is applied onto hard surface of substrate to form film. Photoresist material film is subject to drying until it reaches solid condition. Then surface of photoresist film is subject to effect of pulse laser radiation while shifting laser beam along surface of mentioned film along circular or spiral trajectory by changing frequency of laser radiation pulses in proportion with distance of position of laser beam from center of diffraction areas formed. Then film is developed to get microscopic relief onto its surface. After that the microscopic relief or its mirror reflection is transported onto internal surface of mentioned matrix.

EFFECT: precise representation of microscopic relief of diffraction structure without side marks or any traces of mechanical treatment; higher correction of asymmetric aberration.

13 cl, 11 dwg