23 Jul METHOD FOR MANUFACTURING BIOLOGICAL LENSES FROM DONOR CORNEA
Abstract
FIELD: medical engineering. SUBSTANCE: method involves cutting-off lens with a knife in rotating donor cornea about its axis. Knife blade width and length is not less than lens diameter to be produced. The lens is laid with its cut surface upward on supporting member and circular notch of 4.5 mm diameter is produced with trepan to a depth calculated from formula (1), where DeltaH1 is the trepanation depth, H is the biological lens thickness, R1 is the calculated biological lens convex surface curvature radius; D1 is the optical zone diameter of the biological lens. Corneal tissue is removed with laminating instrument from the optical zone. A circular notch which diameter is less than biological lens diameter not more than by 2.5 mm is produced with the second trepan to a depth calculated from formula (2), where DeltaH2 is the second trepanation depth, D2 is the second trepanation diameter. Corneal tissue is removed with laminating instrument allover the perimeter of the biological lens from its border to the second trepanation depth. EFFECT: increased refraction; created thin fixation wing of negative biological lenses to -30,0 D. 4 dwg
Year: 2004
Country: RU
Doc No: 2222295