Pneumatic vitreotome

A vitreotomy device comprising:

• a body;
• a cannula extending at one end of the body, said cannula presenting a closed distal end and being provided with a window in its side wall close to said distal end;
• a needle driven with reciprocating motion in said cannula to close said window periodically;
• a connecting member configured to connect a suction mechanism to said needle;
• and
• a double-acting cylinder provided with a movable piston for controlling the movement of said needle;
• a return spring interposed between said body and between said piston tending to return said needle towards a second position,
• wherein said needle is driven with reciprocating motion in translation inside said cannula,
• wherein said double-acting cylinder position is secured directly to said needle and extends substantially perpendicularly to the axis of said needle, said movements of the piston being suitable for bringing said needle into a first position in which said needle closes said window, and the second position in which the distal end of the needle is spaced apart from the distal end of the cannula so as to leave said window open,
• wherein said body forms two chambers of said cylinder that are disposed on either side of said piston,
• wherein said piston comprises a plate secured to a proximal-half of said needle and a deformable diaphragm of annular shape having one edge that is secured to a front edge of said plate, the front edge being closer to the distal end of the cannula than its rear edge, and another edge of the deformable diaphragm being secured to said body,
• wherein the proximal end of said needle is connected to the suction mechanism, and
• wherein said body further comprises a first pipe for feeding a first chamber of said two chambers of the cylinder and a second pipe for feeding a second chamber of said two chambers of the cylinder.