Abstract:
A corneal surgical apparatus for incising a cornea of a patient&#39;s eye in a layered form includes: a suction ring unit, having a circular opening, that is to be vacuum-fixed onto a peripheral part of the cornea; a rotatable shaft; an eccentric pin projecting from a distal end of the shaft, the eccentric pin being located at a position offset from a rotational central axis of the shaft; and a cutting unit movable in an incising direction above the suction ring unit. The cutting unit including: cornea applanating means that applanates the cornea within the opening into a substantially flat form; a blade that incises the cornea; a first oscillation transmitting member having a part with which the eccentric pin is engaged; a second oscillation transmitting member having a part with which a part of the first oscillation transmitting member is engaged; and a holder that holds the first and second oscillation transmitting members to be movable in a lateral direction which is perpendicular to the rotational central axis of the shaft. Movement of the second oscillation transmitting member in the lateral direction causes the blade to be moved in the same direction.

Description:
BACKGROUND OF THE INVENTION 
     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 surgery (laser in situ keratomileusis) for the keratorefrative surgery wherein a flap is formed by incising a portion with a thickness of about 0.15 mm 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 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, as shown in FIG. 13A, one comprising a rotation shaft  301  to be rotated by a driving device such as a motor, an eccentric pin  302  provided at the tip end of the shaft  301 , a transmitting member  304  having a vertical groove  303  to be engaged with the pin  302  is proposed. The transmitting member  304  having a blade  300  fixed thereto is held movably in the lateral direction (right and left direction, that is, the direction perpendicular to the paper surface in FIG. 13) in a receiving groove formed in a blade holder  305  and a holder block  306 . When the shaft  301  is rotated by drive of the motor, force is applied on the transmitting member  304  in the lateral direction according to the circumferential movement (circular motion) of the pin  302  engaged with the vertical groove  303 . Accordingly, the transmitting member  304  oscillated laterally (moved in the right and left direction), and further, the blade  300  fixed to the transmitting member  304  is oscillated laterally as well. 
     However, according to the conventional mechanism, as shown in FIG. 13B, by the circumferential movement of the pin  302 , not only the force in the lateral direction but also force in the vertical direction (up and down direction) is applied to the transmitting member  304 . That is, since the pin  302  with the circumferential movement comes in contact with the wall of the vertical groove  303  so that force is applied on the transmitting member  304  in the vertical direction due to the friction force generated by the contact, the transmitting member  304  is oscillated laterally while being moved also in the vertical direction. Therefore, if the shaft  301  is rotated at a high speed, the transmitting member  304  and the blade  300  generate vertical oscillation (up and down movement) called “rampage” in addition to the lateral oscillation. 
     The “rampage” hinders stable incision as well as generates a loss in terms of the efficiency of converting the rotational motion to the lateral oscillation. Moreover, since the corner part of the transmitting member  304  is contacted with a blade holder  305  and the holder block  306  frequently so as to be applied with a large force, the parts are worn out rapidly so that the life cycle thereof is shortened. 
     The displacement amount of the transmitting member  304  to be displaced vertically and laterally (in the up and down, and right and left directions) according to the circumferential movement of the pin  302  corresponds to the eccentric amount of the pin  302 , but as to the vertical direction, since the transmitting member  304  is held by the blade holder  305  and the holder block  306  in the vertical direction, the transmitting member  304  (and the blade  300 ) is displaced (vertical oscillation) for the gap with respect to each member. Therefore, accurate production without a gap among the transmitting member  304 , the blade holder  305  and the holder block  306  would prevent the vertical oscillation (that is, “rampage”), however, much labor is required for meeting the demand particularly in mass production so as to increase the cost. 
     SUMMARY OF THE INVENTION 
     In view of the above-mentioned problems, an object of the present invention is to provide a corneal surgical apparatus capable of forming a good flap by preventing “rampage” of a blade. Effects of the apparatus include efficient generation of lateral oscillation, restraint of the cost rise according to high accuracy of the mechanism, and high durability. 
     In order to solve the above-mentioned problems, the invention is characterized by the following features. 
     (1) A corneal surgical apparatus for incising a cornea of a patient&#39;s eye in a layered form, comprising: 
     a suction ring unit, having a circular opening, that is to be vacuum-fixed onto a peripheral part of the cornea; 
     a rotatable shaft; 
     an eccentric pin projecting from a distal end of the shaft, the eccentric pin being located at a position offset from a rotational central axis of the shaft; and 
     a cutting unit movable in an incising direction above the suction ring unit, the cutting unit including: 
     cornea applanating means that applanates the cornea within the opening into a substantially flat form; 
     a blade that incises the cornea; 
     a first oscillation transmitting member having a part with which the eccentric pin is engaged; 
     a second oscillation transmitting member having a part with which a part of the first oscillation transmitting member is engaged; and 
     a holder that holds the first and second oscillation transmitting members to be movable in a lateral direction which is perpendicular to the rotational central axis of the shaft, 
     wherein movement of the second oscillation transmitting member in the lateral direction causes the blade to be moved in the same direction. 
     (2) A corneal surgical apparatus according to (1), wherein the blade is fixed to the second oscillation transmitting member. 
     (3) A corneal surgical apparatus according to (1), wherein the first oscillation transmitting member includes: 
     a vertical groove elongating in a direction perpendicular to both of the lateral direction and the rotational central axis of the shaft, the eccentric pin being engaged with the vertical groove; and 
     a pin part extending toward the second oscillation transmitting member; 
     wherein the second oscillation transmitting member includes a pin receiving part with which the pin part of the first oscillation transmitting member is engaged. 
     (4) A corneal surgical apparatus according to (1), wherein the holder holds the first and second oscillation transmitting member to be movable linearly in the lateral direction. 
     (5) A corneal surgical apparatus according to (1), wherein the first oscillation transmitting member includes a shaft part rotatable about an axis different in location from the rotational central axis of the shaft, the shaft part having at least one of a recess and a protrusion, and 
     wherein the holder includes a bearing part that rotatably supports the shaft part and that has a part with which the shaft part is engaged, the holder holding the first oscillation transmitting member to be rockable in the lateral direction. 
     (6) A corneal surgical apparatus according to (5), wherein the holder holds the second oscillation transmitting member to be movable linearly in the lateral direction. 
     (7) A corneal surgical apparatus according to (5) , wherein the shaft part of the first oscillation transmitting member includes two shaft parts respectively located on an upper part and a lower part of the first oscillation transmitting member, and 
     wherein the bearing part includes two bearing parts respectively supporting the two shaft parts. 
     (8) A corneal surgical apparatus according to (5), wherein the shaft part of the first oscillation transmitting member is rotatable about an axis intersecting the rotational central axis of the shaft. 
     (9) A corneal surgical apparatus according to (8), wherein the rotational central axis of the shaft part of the first oscillation transmitting member intersects the rotational central axis of the shaft perpendicularly. 
     (10) A corneal surgical apparatus according to (9), wherein the eccentric pin is provided on an axis passing through an intersecting point at which the rotational central axis of the shaft part intersects the rotational central axis of the shaft. 
     (11) A corneal surgical apparatus according to (1), wherein the eccentric pin is provided on an axis non-perpendicularly intersecting the rotational central axis of the shaft. 
     (12) A corneal surgical apparatus according to (1), further comprising: 
     a drive unit that rotates the shaft. 
     (13) A corneal surgical apparatus according to (1), further comprising: 
     a drive unit that moves the cutting unit in the incising direction. 
     (14) A corneal surgical apparatus for incising a cornea of a patient&#39;s eye in a layered form, comprising: 
     a suction ring unit, having a circular opening, that is to be vacuum-fixed onto a peripheral part of the cornea; 
     a rotatable shaft; 
     an eccentric pin projecting from a distal end of the shaft, the eccentric pin being located at a position offset from a rotational central axis of the shaft; and 
     a cutting unit movable in an incising direction above the suction ring unit, the cutting unit including: 
     cornea applanating means that applanates the cornea within the opening into a substantially flat form; 
     a blade that incises the cornea; 
     a rock transmitting member having a part with which the eccentric pin is engaged and a shaft part rotatable about an axis different in location from the rotational central axis of the shaft, the shaft part having at least one of a recess and a protrusion; and 
     a holder that holds the rock transmitting members to be rockable in a lateral direction which is perpendicular to the rotational central axis of the shaft, the holder having a bearing part rotatably supporting the shaft part of the rock transmitting member, the bearing part having a part with which the shaft part is engaged, 
     wherein movement of the rock transmitting member in the lateral direction causes the blade to be moved in the same direction. 
     (15) A corneal surgical apparatus according to (14), wherein the shaft part of the rock transmitting member includes two shaft parts respectively located on an upper part and a lower part of the rock transmitting member, and 
     wherein the bearing part includes two bearing parts respectively supporting the two shaft parts. 
     (16) A corneal surgical apparatus according to (14), wherein the shaft part of the rock transmitting member is rotatable about an axis intersecting the rotational central axis of the shaft. 
     (17) A corneal surgical apparatus according to (16), wherein the rotational central axis of the shaft part of the rock transmitting member perpendicularly intersects the rotational central axis of the shaft. 
     (18) A corneal surgical apparatus according to (17), wherein the eccentric pin is provided on an axis passing through an intersecting point at which the rotational central axis of the shaft part intersects the rotational central axis of the shaft. 
     (19) A corneal surgical apparatus according to (14), wherein the eccentric pin is provided on an axis which non-perpendicularly intersects the rotational central axis of the shaft. 
     (20) A corneal surgical apparatus according to (14), further comprising: 
     a drive unit that rotates the shaft. 
     (21) A corneal surgical apparatus according to (14), further comprising: 
     a drive unit that moves the cutting unit in the incising direction. 
     (22) A corneal surgical apparatus for incising a cornea of a patient&#39;s eye in a layered form, comprising: 
     a suction ring unit, having a circular opening, that is to be vacuum-fixed onto a peripheral part of the cornea; 
     a rotatable shaft; 
     an eccentric pin projecting from a distal end of the shaft, the eccentric pin being provided on an axis non-parallel to and non-perpendicular to a rotational central axis of the shaft; and 
     a cutting unit movable in an incising direction above the suction ring unit, the cutting unit including: 
     cornea applanating means that applanates the cornea within the opening into a substantially flat form; 
     a blade that incises the cornea; 
     a transmitting member having a part with which the eccentric pin is engaged; and 
     a holder that holds the transmitting member to be movable in a lateral direction which is perpendicular to the rotational central axis of the shaft, 
     wherein movement of the transmitting member in the lateral direction causes the blade to be moved in the same direction. 
     (23) A corneal surgical apparatus according to (22), wherein the eccentric pin is provided on an axis that non-perpendicularly intersects the rotational central axis of the shaft. 
     (24) A corneal surgical apparatus according to (22), further comprising: 
     a drive unit that rotates the shaft. 
     (25) A corneal surgical apparatus according to (22), further comprising: 
     a drive unit that moves the cutting unit in the incising direction. 
     The present disclosure relates to the subject matter contained in Japanese patent application Nos. Hei. 11-55696 (filed on Mar. 3, 1999) and Hei. 11-90337 (filed on Mar. 31, 1999), which are expressly incorporated herein by reference in their entireties. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross-sectional view of an apparatus according to a first embodiment and a schematic diagram of a control system. 
     FIG. 2 is an enlarged explanatory diagram of a cutting unit and a suction unit of the apparatus according to the first embodiment. 
     FIG. 3 is a cross-sectional view taken on the line I—I of FIG. 2, illustrating the cutting unit of the apparatus according to the first embodiment. 
     FIG. 4 is a cross-sectional view taken on the line II—II of FIG. 2, illustrating the cutting unit of the apparatus according to the first embodiment. 
     FIGS. 5A and 5B are explanatory diagrams for the movement of two oscillation transmitting members and a blade in the apparatus according to the first embodiment. 
     FIG. 6 is an explanatory diagram for the difference of the blade positions in the conventional apparatus and the apparatus according to the first embodiment. 
     FIG. 7 is a diagram of a modified embodiment of the cutting unit of the apparatus according to the first embodiment. 
     FIG. 8 is a cross-sectional view of an apparatus according to a second embodiment and a schematic diagram of a control system. 
     FIG. 9 is an enlarged explanatory diagram of a cutting unit and a suction unit of the apparatus according to the second embodiment. 
     FIG. 10 is a cross-sectional view taken on the line III—III of FIG. 9, illustrating the cutting unit of the apparatus according to the second embodiment. 
     FIG. 11 is an explanatory diagram for conversion of the motion in the apparatus according to the second embodiment. 
     FIG. 12 is a diagram of a modified embodiment of the cutting unit of the apparatus according to the second embodiment. 
     FIGS. 13A and 13B are explanatory diagrams for the configuration of a cutting unit, and the movement of a transmitting member and a blade in a conventional mechanism. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     &lt;First Embodiment&gt; 
     Hereinafter an embodiment of the invention will be explained with reference to the drawings. FIG. 1 is a cross-sectional view of a corneal surgical apparatus according to a first embodiment and a schematic diagram of a control system. 
     Reference numeral  1  denotes a main body of the apparatus, and numeral  1   a  denotes a grip portion to be held by an operator during a surgery. A suction unit  3  for fixation to the patient&#39;s eye, and a cutting unit  2  having a blade  20  for incising the cornea, to be moved rectilinearly above the suction unit  3  are provided on the front side (left side in the figure) of the main body  1 . 
     A feed motor  11  for rectilinearly moving the cutting unit  2  in the incising direction is fixed in the main body  1 , with a feed screw  13  having a threaded portion corresponding in length to the rectilinear movement of the cutting unit  2 , attached to the rotation shaft of the motor  11 . An oscillating motor  12  for imparting lateral oscillation to the blade, and a connecting member  17  to be connected with the cutting unit  2  at its tip portion are fixed to an attaching member  14  to be screwed into the threaded portion of the screw  13 . A rotation shaft  15  mounted on the rotation shaft of the motor  12  is held by the connecting member  17  rotatably. An eccentric pin  16  is embedded on the tip of the shaft  15  at a position offset from the rotation center (rotation central axis), projecting therefrom. The cutting unit  2  moves forward or backward with the motor  12  and the connecting member  17  mounted on the attaching member  14  according to the forward or reverse rotation of the motor  11 . 
     Next, the configuration of the cutting unit  2  and the suction unit  3  will be explained with reference to FIGS. 2,  3  and  4 . FIG. 2 is an enlarged explanatory diagram of the cutting unit  2  and the suction unit  3  of the apparatus according to the first embodiment. FIG. 3 is a cross-sectional view taken on the line I—I of FIG. 2, and FIG. 4 is a cross-sectional view taken on the line II—II of FIG.  2 . 
     The cutting unit  2  comprises the blade  20 , a blade holder  21   a,  a holder block  21   b,  a first oscillation transmitting member  22 , and a second oscillation transmitting member  23 . A rotation hole in which the shaft  15  is inserted is provided in the holder block  21   b  so that the tip portion of the connecting member  17  is fixed thereto. 
     A metal blade having a blade edge of stainless steel, or steel, or an ore blade having a blade edge of diamond or sapphire is used as the blade  20 . The blade  20  is held between the blade holder  21   a  and the holder block  21   b  laterally oscillatably with an appropriate angle with respect to the horizontal plane. A shallow recess  210   a  is formed at a portion, where the blade  20  is to be placed, at the blade holder  21   a  side. The lateral width of the recess  210   a  is provided larger than the oscillation width of the lateral oscillation of the blade  20 . 
     The first transmitting member  22  is held laterally movably in an oscillating space  210   c  formed in the holder block  21   b.  Further, a vertical groove  22   a  to be engaged with the pin  16  is formed in the first transmitting member  22 . When the shaft  15  is rotated by the rotation drive of the motor  12 , a lateral force is applied to the first transmitting member  22  according to the circumferential movement of the pin  16  engaged with the vertical groove  22   a.  Accordingly, the first transmitting member  22  oscillates laterally. 
     The second transmitting member  23  is held laterally movably in an oscillating space  210   b  formed in the holder block  21   b.  Further, a vertical groove  23   a  to be engaged with a pin part  22   b  provided below the first transmitting member  22  is formed in the second transmitting member  23 . When the first transmitting member  22  is oscillated laterally by the rotation of the shaft  15  (circumferential movement of the pin  16 ), the lateral oscillation provides a lateral force to the second transmitting member  23  via the pin part  22   b  and the vertical groove  23   a.  Accordingly, the second transmitting member  23  oscillates laterally, and further, the blade  20  fixed to the second transmitting member  23  oscillates laterally as well. 
     The movement of the first transmitting member  22 , the second transmitting member  23 , and the blade  20  will be explained with reference to FIGS. 5A and 5B. 
     The first transmitting member  22  moves reciprocally in the lateral direction (X direction) (this will be referred to as a first lateral oscillation) as well as moves reciprocally in the vertical direction (Y direction) (this will be referred to as a first vertical oscillation) according to the circumferential movement of the pin  16  according to the rotation of the shaft  15  (according to split of the force generated by the circumferential movement of the pin  16  into the pushing force for pushing the side surface of the vertical groove  22   a  and the friction force functioning in the vertical direction on the side surface of the vertical groove  22   a ) as shown in FIG.  5 A. The dashed line D 1  in the figure denotes the locus of the movement of the point P, which is the center of the pin part  22   b.    
     The second transmitting member  23  moves reciprocally in the lateral direction (X direction) (this will be referred to as a second lateral oscillation) as well as slightly moves reciprocally in the vertical direction (Y direction) (this will be referred to as a second vertical oscillation) according to the movement of the pin part  22   b  of the first transmitting member  22  as shown in FIG.  5 B. The dashed line D 2  in the figure denotes the locus of the movement of the point Q, which is the center of the blade  20 . 
     The displacement amount in the lateral direction according to the first vertical oscillation is based on the distance of the gap between the first transmitting member  22  and the holder block  21   b.  In contrast, the displacement amount in the vertical direction according to the second vertical oscillation is much smaller than that of the first vertical oscillation because the circumferential movement of the pin  16  is converted to the first lateral oscillation already, thereby generating the second lateral oscillation (the displacement amount in the lateral direction of the first lateral oscillation and the second lateral oscillation is same, and it corresponds to the eccentric amount of the pin  16 ). Moreover, the displacement amount difference in the vertical direction according to the second vertical oscillation derived from the gap at the time of generating the first lateral oscillation and the gap at the time of generating the second vertical oscillation is small because the displacement amount itself is extremely small. 
     As mentioned above, the locus D 2  has a smaller displacement amount in the vertical direction compared with the locus D 1 . That is, the second transmitting member  23  has a smaller displacement amount in the vertical oscillation at the time of the lateral oscillation with respect to the first transmitting member  22 . Accordingly, the “rampage” can be restrained at the time of the lateral oscillation. 
     Furthermore, as shown in FIG. 6, according to the conventional apparatus configuration, the position of a blade  400  in the up and down direction is limited due to the radius (diameter) of a rotation shaft  401 , the circumferential movement of an eccentric pin  402 , and the displacement amount in the vertical direction (vertical groove  403 ). In contrast, according to an apparatus of the invention, since the position of the blade  20  in the up and down direction is limited onto to the displacement amount in the vertical direction (vertical groove  23   a ), and further, the displacement amount in the vertical direction is smaller than the conventional configuration, the point of action for transmitting the lateral oscillation to the second transmitting member  23  can be provided adjacent to the blade  20 , to which the load is applied. Therefore, the second transmitting member  23  can be made smaller than the conventional transmitting member  404  (see FIG.  7 ). Accordingly, the rotation torque applied on the blade  20  is smaller than the conventional configuration, and thus the blade  20  can efficiently be oscillated laterally so that the “rampage” can be smaller. 
     In FIG. 2, a cornea applanating part  24  is fixed to the holder block  2 l b  by an attaching member  24   a  so as to be provided on the front side (left side in the figure) of the blade  20 . The cornea applanating part  24  moves according to the movement of the cutting unit  2  for applanating the cornea of the patient&#39;s eye flatly preceding incision with the blade  20 . Since the blade  20  incises the cornea thus applanated flatly by the applanating part  24 , a flap of a uniform layer is formed. The distance between the edge of the blade  20  attached to the blade holder  21   a  and the lower surface of the applanating part  24  is about 150 μm so that the cornea can be incised with this thickness in a layered form. 
     The suction unit  3  comprises a fixing member  30 , a suction ring  31 , and a suction pipe  32 . The suction ring  31  is fixed to the main body  1  by the fixing member  30 . The suction ring  31  having a substantially cylindrical shape with a U-shaped cross-section, comprises a circular recess  31   a  to be contacted with the patient&#39;s eye and an opening  31   b  concentric with the recess  31   a.  When the suction ring  31  is set on the patient&#39;s eye for surgery, the cornea of the patient&#39;s eye projects upward from the opening  31   b  so that the lower end portion of the suction ring  31  and the opening end portion of the opening  31   b  are contacted so as to provide a space S for suction. 
     The suction pipe  32  is embedded in the suction ring  31 , and connected with a vacuum tube (not illustrated) elongating to a pump  41 . A suction path  32   a  provided inside the suction pipe  32  communicates with the recess  31   a.  According to suction and discharge of the air in the space S by the pump  41  via the suction path  32   a,  the suction ring  31  is vacuum-fixed to the patient&#39;s eye. In this fixation, as the operator holds the grip portion  1   a,  positioning of the opening  31   b  can be facilitated, and the apparatus can be held stably. 
     In addition, a pipe for pressure detection (not illustrated) is embedded in the suction ring  31  at a position facing to the suction pipe  32 . The pipe for pressure detection is connected with a pressure detector  33  via a tube (not illustrated). The pressure detector  33  detects the air pressure in the space S sucked by the pump  41  via the pipe for pressure detection. A control unit  40  controls the operation of the motor  11 , the motor  12 , and the pump  41  based on the air pressure detected by the pressure detector  33 . 
     Hereinafter the operation of the apparatus with the above-mentioned configuration will be described. While confirming the state of inclination of the suction ring  31  (main body  1 ) and the position of the pupillary center based on a mark applied on the cornea of the patient&#39;s eye with an instrument such as a marker, the operator positions the center of the opening  31   b  with respect to the pupillary center and disposes the suction ring  31  on the patient&#39;s eye. 
     After installation of the suction ring  31 , the operator operates the pump  41  so as to suck the air in the space S between the suction ring  31  and the patient&#39;s eye while keeping the position and the posture of the main body  1  for thereby reducing the air pressure (to the negative pressure). When the air pressure in the space S is reduced to a certain value (when it reaches a sufficiently negative pressure), the operation of the pump  41  is controlled by the control unit  40  so as to maintain the air pressure. Accordingly, the suction ring  31  is vacuum-fixed onto the patient&#39;s eye. 
     After completion of the fixation of the apparatus, the operator operates a foot switch  42  for rotation drive of the motor  11  and the motor  12 . The control unit  40  controls for rotation drive of the motor  11  and the motor  12 . The control unit  40  controls the drive of the motor  12  by the input of a drive command signal by the foot switch  42  so as to oscillate the blade  20  laterally by a fixed or variable oscillation frequency. Further, the control unit  40  controls the rotation of the motor  11  according to a fixed or variable feeding speed so as to rectilinearly move the cutting section  2  in the hinge direction. At the time, the shaft  15  slides in the advancing direction integrally with the cutting unit  2  while making a rotational motion for imparting lateral oscillation to the blade  20 . 
     After being converted to the lateral oscillation of the first transmitting member  22 , the rotational motion of the shaft  15  is converted to the lateral oscillation of the second transmitting member so as to provide the rectilinear oscillation to the blade  20 , and thus the “rampage” caused by the vertical oscillation can be restrained so as to form a good flap stably. 
     When the edge of the blade  20  has incised the cornea with the hinge portion left so as to complete the flap formation, the motor  11  is rotated reversely so as to return the cutting unit  2  to its initial position. At the time, the rotation of the motor  12  is stopped according to the independent control of the motors so that the blade  20  can be taken out from the flap while avoiding the unnecessary oscillation of the blade  20 . Accordingly, the possibility of cut off of the thus formed flap can be reduced. 
     After the return of the cutting unit  2  to the initial position, air is introduced into the space S so as to release the suction for removing the apparatus (suction ring  31 ). Subsequently, the corneal stroma is ablated for the refractive correction amount, and then the flap is returned to its original position so as to finish the surgery. 
     Although the first transmitting member  22  comprising the vertical groove  22   a  to be engaged with the pin  16  and the pin part  22   b,  and the second transmitting member  23  comprising the vertical groove  23   a  to be engaged with the pin part  22   b  of the first transmitting member  22  (in this case, the blade  20  is fixed to the second transmitting member  23 ) are used in this embodiment for converting the rotation of the shaft  15  (circumferential movement of the pin  16 ) to the lateral oscillation of the blade  20 , it is also possible to further provide a pin part similar to the pin part  22   b  in the second transmitting member and a third oscillation transmitting member comprising a vertical groove to be engaged with the pin part of the second transmitting member. In this case, the blade is fixed to the third transmitting member. That is, although the rotation of the rotation shaft is converted to the lateral oscillation of the blade by the conversion by twice, but the conversion needs to be at least twice and can be increased to three times or four times. 
     &lt;Second Embodiment&gt; 
     Another embodiment of the invention will be explained with reference to the drawings. FIG. 8 is a cross-sectional view of an apparatus according to the second embodiment and a schematic diagram of a control system. FIG. 9 is an enlarged cross-sectional view of a cutting unit  2  and a suction unit  3 . FIG. 10 is a cross-sectional view taken on the line III—III of FIG.  9 . The same numerals are applied to the same components as in the first embodiment. 
     The cutting unit  2  comprises the blade  20 , the blade holder  21   a,  the holder block  21   b,  a bearing part  21   c,  a rock (swing) transmitting member  25 , and a lateral oscillation transmitting member  26 . A rotation hole in which the shaft  15  is inserted is provided in the blade holder  21   a  so that the tip portion of the connected member  17  is fixed thereto. 
     The rock transmitting member  25  is pivoted by the holder block  21   b  and the bearing part  21   c  rotatably (rockably) with two upper and lower rotation shaft parts  25   c  as the rotation central axes in the oscillation space  210   c  formed in the holder block  21   b  (that is, the rock transmitting member  25  is pivoted rockably in the lateral direction, centering the axial line L elongating in the vertical direction). Further, a vertical groove  25   a  to be engaged with the pin  16  is formed in the rock transmitting member  25 . When the shaft  15  is rotated according to the rotation drive of the motor  12 , a force in the lateral direction is applied on the rock transmitting member  25  by the circumferential movement of the pin  16  engaged with the vertical groove  25   a.  Accordingly the rock transmitting member  25  is rocked. 
     The lateral oscillation transmitting member  26  is held movably in the lateral direction in the oscillation space  210   b  formed in the holder block  21   b.  A pin receiving part  26   a  to be engaged with the a pin part  25   b  provided at a lower portion of the rock transmitting member  25  is formed in the lateral oscillation transmitting member  26 . When the rock transmitting member  25  is rocked in the lateral direction with the shaft parts  25   c  as the rotation center by the rotation of the shaft  15  (circumferential movement of the pin  16 ), a force in the lateral direction is applied on the lateral oscillation transmitting member  26  via the pin part  25   b  and the pin receiving part  26   a  according to the rock. Accordingly, the lateral oscillation transmitting member  26  oscillates laterally, and further, the blade  20  fixed to the oscillation transmitting member  26  oscillates laterally as well. 
     The movement of the pin  16 , the rock transmitting member  25 , the lateral oscillation transmitting member  26 , and the blade  20  will be explained with reference to FIG.  11 . 
     When the shaft  15  is rotated by the motor  12 , the projecting portion of the pin  16  provided eccentrically in the shaft  15  moves circumferentially, centering the rotation central axis of the shaft  15 . The force generated by the circumferential movement of the pin  16  can be split in the vertical and lateral directions, that is, the force in the vertical direction functioning on the side surface of the vertical groove  25   a  in the up and down direction as the friction force, and the force in the lateral direction pushing the side surface of the vertical groove  25   a  in the lateral direction as the pushing force. According to the force applied on the side surface of the vertical groove  25   a,  the rock transmitting member  25  rocks with the shaft parts  25   c  as the rotation center. Since the shaft parts  25   c  are held sufficiently by the holder block  21   b  and the bearing part  21   c  with respect to the force in the vertical direction generated by the pin  16 , the “rampage” in the vertical direction an be restrained so that the rotational motion of the shaft  15  can be converted efficiently to the rock of the rock transmitting member  25 . 
     According to the rock of the rock transmitting member  25  in the lateral direction, the pin part  25   b  formed in the lower portion thereof is rocked in the lateral direction with substantially no displacement in the vertical direction. Since the pin part  25   b  rocking in the lateral direction applies a force on the side surface of the pin receiving part  26   a,  the lateral oscillation transmitting member  26  oscillates in the lateral direction with the oscillation space  210   b  as the guide. At the time, by providing a substantially spherical tip end shape to the pin part  25   b,  a force can be applied efficiently to the pin receiving part  26   a  so that the lateral oscillation can be provided smoothly. Since the blade  20  is fixed to the lateral oscillation transmitting member  26 , it oscillates according to the lateral oscillation of the lateral oscillation transmitting member  26 . 
     According to the configuration, after being converted to the rock with the shaft parts  25   c  of the rock transmitting member  25  as the rotation center, the rotational motion of the shaft  15  applies rectilinear oscillation to the blade  20  in the lateral direction. Since the force according to the circumferential movement of the pin  16  in the vertical direction is supported by the shaft parts  25   c,  the “rampage” by the vertical oscillation can be restrained so that a good flap can be formed stably. Moreover, since the sliding portion is only in the peripheral part of the shaft parts  25   c,  worn out of the oscillating portion can be restrained so as to prolong the life cycle of the parts. 
     The pin  16  can be attached to the shaft  15 , elongating parallel in the rotation central axis direction of the shaft  15  (as in the conventional apparatus shown in FIG.  13 A), but the pin  16  is provided tilting with respect to the rotation central axis direction of the shaft  15  in this embodiment. That is, the pin  16  is provided eccentrically, elongating passing through the intersection of the axial line L passing through the rotation center of the rock of the rock transmitting member  25  and the rotation central axis of the shaft  15 . According to the configuration, since the rocking angle of the pin  16  in the lateral direction and the rocking angle of the rock transmitting member  25  in the lateral direction coincide, the contacting property of the pin  16  engaged with the vertical groove  25   a  is improved and thus the rotational motion can be converted smoothly and efficiently to the lateral rock. Moreover, the shape of the vertical groove  25   a  and the tip end portion shape of the pin  16  to be engaged therewith can be a simple shape (linear shape) so that the production of components can be facilitated. 
     Furthermore, although the rock of the pin part  25   b  is converted to the linear lateral oscillation of the lateral oscillation transmitting member  26  in this embodiment, it is also possible to fix the pin part  25   b  and the lateral oscillation transmitting member  26 , rock the lateral oscillation transmitting member  25 , and have arc-like oscillation of the blade  20 . Moreover, as shown in FIG. 12, the rock transmitting member  25  can be eliminated. 
     Furthermore, the rock transmitting member  25  needs to rock with oscillation with a lateral direction component for oscillating the blade  20  in the lateral direction, and therefor, the axial line L to be the center of the rock should be provided at a position offset from the rotation central axis of the shaft  15 . For the efficient conversion of the rotation of the shaft  15  into the oscillation of the lateral direction component, it is preferable that the axial line L to be the center of the rock is in the same plane as the rotation central axis of the shaft  15 , and further, it is preferable that the axial line L as the rocking center is disposed in the plane in the vertical direction passing through the rotation central axis of the shaft  15  with respect to the lateral direction for oscillating the blade  20 , and the rock transmitting member  25  is rocked with the axial line L as the center. The conversion efficiency of the oscillation in the lateral direction can be most efficient by providing the axial line L orthogonal to the rotation central axis of the shaft  15  as in this embodiment. 
     Moreover, the vertical groove  25   a  formed in the rock transmitting member  25  can be provided at the grip portion  1   a  side with respect tot he rotation center of the shaft parts  25   c.  Furthermore, by changing the distance of the vertical groove  25   a  and the distance of the pin  25   b  from the rotation center of the shaft parts  25   c,  respectively, the width of the lateral oscillation of the blade  20  with respect to the eccentric amount of the pin  16  can be adjusted freely (it is also possible to enlarge the oscillation width with a small eccentric amount). 
     Moreover, although explanation has been given with the motor  12  for rotating the shaft  15  in this embodiment, an air turbine can be used as well. Furthermore, as the mechanism for feeding the blade, a mechanism for incising the cornea by rotational movement of the blade as disclosed in JP-A-11-19115 and JP-A-11-99167 filed by the present inventor can be adopted as well. 
     As heretofore explained according to the invention, a good flap can be formed by preventing the “rampage” of the blade. 
     Moreover, the lateral oscillation of the blade can be generated efficiently, the cost rise according to the high accuracy of the mechanism can be restrained, and the durability of the mechanism is improved so as to prolong the life cycle.