referring now to fig1 , an embodiment of a laser eye surgery system 10 of the present invention includes a magnification system or microscope 12 through which an eye e of a patient is viewed , typically while the eye e is ablated by a laser beam 14 . in preferred embodiments , the microscope 12 comprises a leica ms5 microscope , however any suitable microscope or microscope components may be used . the eye e may be viewed by a surgeon through eyepieces 18 on the microscope 12 . the microscope 12 includes , among other components , knobs 22 for adjusting the magnification of the microscope 12 . thus , by rotation of the knobs 22 , the eye e may be viewed under varying levels of magnification through the eyepieces 18 . in addition , laser eye surgery system 10 of the present invention includes a monitor display 16 which provides an image 20 of the eye e as viewed through the eye pieces 18 . this allows the surgeon and any other assistants or practitioners to easily view the eye e throughout the surgical procedure without approaching the eyepieces 18 of the microscope 12 . the display 16 may also provide additional information related to the procedure and provide a user interface with the use of a keyboard 24 for user input . the image 20 of the eye e may include a pupil image 30 having a pupil / iris boundary 32 , an iris image 34 having a limbus 36 , and a sclera image 37 as shown on the display 16 of fig1 . at the start of the surgical procedure , the eye e is aligned with the desired path of the laser beam 14 by centering a target tissue area of the eye e with the center of a fixed reticle 40 . the fixed reticle 40 may be viewed through the eyepieces 18 and is also projected into the image 20 for viewing on the display 16 . in this example , the pupil image 30 is centered to be aligned with the center of the fixed reticle 40 . fig2 a provides a closer view of the display 16 of fig1 having the pupil image 30 aligned with the center of the fixed reticle 40 . as mentioned , the eye e typically moves both voluntarily and involuntarily while the eye e is generally aligned . such movement is tracked by an eye tracker . tracking by following the subject eye tissue , i . e ., recognizing new locations of the same tissue and readjusting the imaging system and the surgical laser aim to the new location , assures that the laser , when firing through a prescribed ablation pattern , will not deviate from the pattern an unacceptable distance . fig2 b illustrates the eye e having moved away from its previous position during tracking . software included in the system 10 projects onto the display 16 a moving cross - hair 42 which tracks the previously centered eye tissue ( in this case the center of the pupil ). as shown , the moving cross - hair 42 may be displaced from the fixed reticle center 40 by an x - distance 44 along an x - axis and a y - distance 46 along a perpendicular y - axis . in addition , the moving cross - hair 42 may rotate in relation to the fixed reticle center 40 , as shown . by rotation of the knobs 22 , the eye e may be viewed under varying levels of magnification . as the magnification level is changed , the image 20 on the display 16 is appropriately scaled to show the image 20 at the new magnification level . in addition , the fixed reticle 40 and the moving cross - hair 42 are also scaled in size and position to reflect the new magnification level . fig2 c illustrates the image 20 of fig2 b at a higher level of magnification . as shown , the size of the reticle 40 and cross - hair 42 are appropriately larger and the cross - hair 42 is displaced by x ′- distance 50 along the x - axis and y ′- distance 48 along the perpendicular y - axis , wherein x ′ and y ′ are scaled to reflect the magnification level . thus , the cross - hair 42 maintains representation of tracking the previously centered eye tissue ( in this case the center of the pupil ). such rescaling is achieved with software of the laser eye surgery system 10 . fig3 provides a schematic illustration of a portion of the microscope 12 of the laser eye surgery system 10 . this portion includes a microscope body 60 having a microscope top 62 . viewholes 64 are visible through the microscope top 62 which allow viewing through the eyepieces ( not shown ) and the microscope body 60 . in addition , the portion includes knobs 22 for adjusting the magnification level . typically , a magnification setting indicator 66 is present to display the magnification level . in this illustration , an indicator 66 is positioned near the rotating knob 22 displaying the level “ 2 . 5 ”. it may be appreciated that the indicator 66 may be present at any location ( s ) including the display 16 . the leica ms5 microscope has six magnification position settings . the six positions are continuous wherein the magnification knob has no 360 degree rotation stops , the knob 22 rotated beyond 360 degrees repeats the six magnification settings . table 1 provided in fig4 shows the possible magnification settings of this embodiment . the present invention includes a magnification setting sensor system which informs the laser eye surgery system software of the magnification setting . fig5 illustrates an embodiment of the magnification setting sensor system 70 . the sensor system 70 comprises a magnification sensor body 72 including at least one opto - sensor , in this embodiment three opt - sensors ( s 0 , s 1 , s 2 ) are present . the opto - sensors s 0 , s 1 , s 2 are disposed on a printed circuit board ( pcb ) 80 with a cable connection to the rear of the magnification sensor body 72 . the cable connection is db9m ; the pin - outs for the db9m connection are presented in table 2 of fig6 . the sensor system 70 also includes a gray scale encoder 74 . the encoder 74 is positioned between the magnification sensor body 72 and the knob 22 . the encoder 74 and knob 22 are attached to a knob shaft 76 so that rotation of the knob 22 rotates the encoder 74 in addition to rotating a magnification carousel 78 which provides lenses to magnify the viewed object , in this case the eye e . fig7 illustrates the gray scale encoder 74 engaged with the pcb 80 . as shown , the opto - sensors s 0 , s 1 , s 2 are shaped to extend over a lip 82 on the encoder 74 . when the encoder 74 is rotated through the magnification settings or rotation stops by rotation of the knob 22 , the lip 82 is also rotated through the rotation stops . since the lip 82 extends only along a portion of the encoder 74 , in this embodiment along 180 degrees of the encoder 74 , the presence of the lip 82 is sensed by the sensors s 0 , s 1 , s 2 as the encoder 74 is rotated in either the clockwise or counter - clockwise direction . sensing of the presence of the lip 82 of the gray scale encoder 74 provides a gray scale code which indicates the rotation stop that the knob 22 has been turned to , which in turn indicates the magnification setting of the microscope . the gray scale code is a variation of the standard binary code in which only one bit changes at a time between successive binary digits . fig8 provides table 3 which shows the detent positions of the knob 22 with corresponding detent degree positions , corresponding gray scale codes and corresponding magnification settings . fig9 a - 9d further illustrate the generation of the gray scale code by the magnification setting sensor system 70 . fig9 a illustrates the view from the pcb circuit side looking through the pcb back at the gray scale encoder . in this embodiment , the opto - sensors s 0 , s 1 , s 2 are disposed at the 30 , 90 , 150 degree positions respectively . the opto - sensors remain stationary as the gray scale encoder rotates . fig9 a also illustrates the locations of the six detents disposed 60 degrees apart , at 0 , 60 , 120 , 180 , 240 and 300 degrees . fig9 b - 9d illustrate the movement of the lip 82 ( indicated by shading ) as the gray scale encoder 74 is rotated through the detents . fig9 b illustrates the encoder 74 at the first detent wherein the lip 82 is sensed by all three opto - sensors s 0 , s 1 , s 2 . this provides a gray scale code of 111 . the gray scale code is transmitted from the pcb 80 to the system controller of the laser eye surgery system 10 . the system controller software determines if valid magnification position settings are being sent from the pcb 80 . referring to table 3 of fig8 , a gray scale code of 111 corresponds to a magnification setting of 1 . 0 . thus , the system software appropriately scales the size and position of the reticle 40 and cross - hair 42 on the image 20 , as described and illustrated in fig2 a - 2c , to reflect the magnification setting of 1 . 0 . in addition , the system software may display the sensed magnification setting . fig9 c illustrates rotation of the encoder 74 counter clockwise ( ccw ) to the second detent wherein the lip 82 is rotated so that the lip 82 is sensed by opto - sensors s 1 , s 2 . this provides a gray scale code of 110 . referring to table 3 of fig8 , a gray scale code of 110 corresponds to a magnification setting of 0 . 63 . thus , the system software appropriately scales the size and position of the reticle 40 and cross - hair 42 on the image 20 , as described and illustrated in fig2 a - 2c , to reflect the magnification setting of 0 . 63 . in addition , the system software may display the sensed magnification setting . fig9 d illustrates rotation of the encoder 74 counter clockwise ( ccw ) to the third detent wherein the lip 82 is rotated so that the lip 82 is sensed by opto - sensor s 2 . this provides a gray scale code of 100 . referring to table 3 of fig8 , a gray scale code of 100 corresponds to a magnification setting of 1 . 6 . thus , the system software appropriately scales the size and position of the reticle 40 and cross - hair 42 on the image 20 , as described and illustrated in fig2 a - 2c , to reflect the magnification setting of 1 . 6 . in addition , the system software may display the sensed magnification setting . it may be appreciated that rotation of the encoder 74 through the remaining detent positions will continue rotating the lip 82 and providing gray scale codes in the same manner . in this way , the magnification settings are transmitted through the system software to be used in conjunction with the display . the magnification setting sensor system 70 is a compact system which is easily incorporated into existing microscopes . as shown in fig1 , the sensor system 70 is disposed within the microscope body 60 , between the magnification carousel 78 and the knob 22 . thus , the knob 22 and magnification setting indicator 66 may appear identical to a standard microscope so that the magnification setting sensor system 70 is an unobtrusive addition to the laser eye surgery system 10 . although the foregoing invention has been described in some detail by way of illustration and example , for purposes of clarity of understanding , it will be obvious that various alternatives , modifications and equivalents may be used and the above description should not be taken as limiting in scope of the invention which is defined by the appended claims .
devices , systems and methods for scaling the size and / or position of a marker on a magnified image of an object . in preferred embodiments , the object is an eye that is undergoing laser eye surgery . the eye is viewed through a magnification system or microscope and an image of the eye is presented on a display . one or more markers are present on the image , each identifying a specific target location or landmark on the eye . when a desired magnification setting is selected , the image is scaled accordingly . in addition , one or more of the markers is scaled in size and / or position to reflect the magnification setting . this allows the marker to maintain identification of the target location while reflecting the selected magnification level .