1. Field of the Invention
The present invention relates to a corneal surgical apparatus for incising the cornea of an eye of a patient in a layered form at the time of a keratorefrative surgery or the like.
2. Description of the Related Art
In recent years, attention has been focused on a LASIK (laser in situ keratomileusis) surgery for the keratorefractive surgery wherein a flap is formed by incising a corneal portion with a thickness of about 0.15 mm ranging from the corneal epithelium to the corneal stroma with a part of the cornea remaining connected like a hinge, ablating the corneal stroma in a refractive correction amount by an excimer laser light, and returning the flap to its original position. In the LASIK surgery, a corneal surgical apparatus called a microkeratome is used for incising the cornea in a layered form.
As a corneal surgical apparatus, one comprising a suction ring to be vacuum-fixed to a part of the cornea from a corneal ring portion to the surface of the conjunctiva, a cornea applanating member for applanating the cornea flatly, and a blade movable toward the hinge while being oscillated laterally so as to incise the flattened cornea into a layer form with a substantially uniform thickness, is known.
As a mechanism for the blade lateral oscillation, one comprising a motor, a rotation shaft to be rotated by the motor, a bearing rotatably supporting the rotation shaft, and a transmitting member, such as an eccentric pin, for converting the rotation of the motor transmitted through the rotation shaft into the lateral oscillation to be transmitted to the blade, is proposed. To incise the cornea uniformly and easily, the blade is required to be oscillated laterally at a high speed, and thus the motor rotates the rotation shaft at a high speed to rotate the eccentric pin on the rotation shaft at a high speed.
However, since the rotation shaft is required to laterally oscillate the relatively heavy blade and transmitting member through the eccentric pin, the rotation of the rotation shaft (i.e. the rotation at the blade side of the rotation shaft) is slightly varied or shifted. For this reason, liquid, such as ophthalmic solution (physiological saline) applied to the patient""s eye during surgery and tear liquid, may penetrate or infiltrate into a small clearance between the rotation shaft and the bearing. This will cause erosion and short circuit of an electric system, and thus is not preferable.
In order to solve the above-noted problem, the present invention provides the following arrangements:
(1) A corneal surgical apparatus for incising a cornea of a patient""s eye in a layered form, comprising:
a blade;
a rotating shaft;
a bearing rotatably supporting the rotating shaft;
transmitting means for converting rotation of the rotating shaft about a rotation center axis into oscillation in a direction perpendicular to the rotation center axis and transmitting the oscillation to the blade; and
preventing means for preventing moisture component from penetrating into a clearance between the rotating shaft and the bearing by controlling the rotation of the rotating shaft.
(2) The apparatus of (1), wherein the preventing means includes correcting means for correcting rotation shift of the rotating shaft in the direction perpendicular to the rotation center axis.
(3) The apparatus of (2), wherein the correcting means causes the rotation shift of the rotating shaft entirely over and along the rotation center axis.
(4) The apparatus of (2), wherein the correcting means includes a weight member attached to at least one of an outer side of the rotating shaft and an inner side of the rotating shaft.
(5) The apparatus of (4), wherein the weight member is attached to the rotating shaft at a predetermined position opposite from a blade side of the rotating shaft.
(6) The apparatus of (1), wherein the transmitting means includes an eccentric pin that is projectingly provided on a blade side leading end of the rotating shaft and that is offset from the rotation center axis.
(7) The apparatus of (1), further comprising:
a liquid reservoir, provided to at least one of the rotating shaft and the bearing, for accumulating lubricant applied to the clearance between the rotating shaft and the bearing.
(8) The apparatus of (1), further comprising:
a drive unit for rotating the rotating shaft.
(9) The apparatus of (1), further comprising:
translating means for moving the blade in an incise direction.
(10) The apparatus of (9), wherein the translating means includes a drive unit for moving the rotating shaft in an incise direction.
(11) A corneal surgical apparatus for incising a cornea of a patient""s eye in a layered form, comprising:
a blade;
a rotating shaft having a blade side close to the blade and an opposite side opposite from the blade with respect to the blade side, wherein a center of gravity of the opposite side is offset from a rotation center axis of the rotating shaft;
a bearing rotatably supporting the rotating shaft;
an eccentric pin that is projectingly provided on a blade side leading end of the rotating shaft and that is offset from the rotation center axis; and
a transmitting member having a groove engaged with the eccentric pin, the transmitting member being supported movably in a direction perpendicular to the rotation center axis.
(12) The apparatus of (11), wherein the center of gravity of the opposite side of the rotating shaft is offset to have a predetermined relationship with respect to an offset position of the eccentric pin.
(13) The apparatus of (11), wherein a weight member is provided to the rotating shaft so that the weight member is located on at least one of an inner side of the rotating shaft and an outer side of the rotating shaft and on the opposite side.
(14) The apparatus of (11), wherein at least one of the rotating shaft and the bearing have a liquid reservoir for accumulating lubricant applied to the clearance between the rotating shaft and the bearing.
(15) A transmitting mechanism, in a corneal surgical apparatus, for converting inputted rotation into oscillation and transmitting the oscillation to a blade, the transmitting mechanism comprising:
a rotating shaft having a first side to which the rotation is inputted and a second side opposite from the first side;
a bearing rotatably supporting the rotating shaft;
a first, discrete unbalance component provided to the first side, and
a second, discrete unbalance component provided to the second side.
(16) The mechanism of (15), wherein the first component includes a weight member, and the second component includes an eccentric pin.
The present disclosure relates to the subject matter contained in Japanese patent application No. 2000-630 (filed on Jan. 6, 2000), which is expressly incorporated herein by reference in its entirety.