The present invention relates generally to instruments and methods used in ophthalmic surgery and, more particularly, to instruments and methods used to mark the cornea prior to ophthalmic operations, such as the implantation and alignment of an intraocular lens (IOL) or laser-assisted in-situ keratomileusis (LASIK).
Replacement of a cataract with an artificial IOL is now a well-accepted surgical procedure. Typically, during such a procedure the diseased lens is removed from the capsular bag by phacoemulsification and a soft, plastic IOL is folded, inserted into the capsular bag and allowed to unfold to act as a replacement lens.
Early implantable IOLs did not afford any correction for corneal astigmatism and a patient suffering from such a condition would still have to wear glasses even after the cataract was removed and a new lens inserted in its place. Alcon Industries has developed its AcrySof® toric IOL which combines the flexibility of an implantable IOL with the astigmatic corrections available in typical glass or plastic eyeglass lenses. In order to use a toric IOL effectively, the lens must be rotated in the capsular bag to align the lens with a pre-calculated optimal axis, typically the steepest curvature of the cornea. To do so, a keratometer is used to measure the curve of the patient's cornea and to determine the steep axis of the cornea. When the toric IOL is implanted, a pair of reference marks on the toric IOL are aligned with the steep axis to provide the desired vision correction. As used herein, the term “keratometer” also refers to a corneal measuring device that includes means for placing marks on the cornea.
It is important to have an accurate measurement of the corneal curvature and equally important to find a method for identifying the steep axis during surgery so the IOL can be aligned properly.
It is important to have an accurate measurement of the corneal curvature and equally important to find a method for identifying the steep axis during surgery so the IOL can be aligned properly.
The present invention relates to instruments which are used to mark the cornea of the patient to identify pre-phacoemulsification reference points to determine the orientation of the steep axis of the cornea so that after phacoemulsification the IOL can be rotated to align it properly with the steep axis.
Prior to phacoemulsification the patient's eye is examined with a keratometer and a toric IOL calculator is then used to determine the angle of the steepest, or “steep” axis along which the astigmatism is most pronounced and with which the lens needs to be aligned. The angle is then recorded so the IOL can be accurately assigned when inserted into the eye.
In preparation for surgery, the patient is seated in an upright position and a corneal marker is used to mark the 3-, 6- and 9 o'clock positions on the cornea, with the 3- and 9-o'clock positions corresponding to the corners of the eye and the 6 o'clock position corresponding to the bottom of the eye. These will be the reference points for later marking of the steep axis.
The corneal marker includes a series of tabs formed on the front surface of a circular ring, placed at 90° intervals. The rear of the ring includes a number of marking tabs intended to come into contact with the cornea. After the marking tabs are coated with dye, one marking tab is aligned with the limbus of the eye and the instrument is then pressed against the cornea to leave marks corresponding to the 3-, 6- and 9 o'clock positions.
A second corneal marker, made specifically for marking the steep axis has a pair of axis marking tabs on the rear and a scale on the front, marked in degrees. Some corneal markers may also include a rotating ring, commonly mounted within a fixed ring, with the fixed ring used to mark the reference points and a rotating ring used to mark the steep axis. The rotating ring has a pair of axis marking tabs formed on its rear surface.
When the patient is ready for surgery, one of the corneal markers described above is used to mark the steep axis. If the second corneal marker has a fixed set of tabs, the scale on the front of the marker is read to correspond with the steep axis by aligning the axis reading with the reference points already present on the cornea. If a corneal marker with a rotating ring is used, the marker is aligned with the reference points and the ring is rotated until the steep axis setting is reached and the marker is allowed to come into contact with the cornea to press the axis tabs, aligned with the angle marking on the marker, against the cornea. The axis tabs make a pair of marks on the cornea, and it is this second set of reference marks that identifies the axis with which the IOL is aligned when 5 it is inserted so that the stigmatic correction of the IOL is maximized.
The corneal marker will work more accurately to make the reference marks if it is held in a horizontal position when the patient is sitting up. To position the marker, the user holds it to align the handle in a generally horizontal orientation. The marker will work most accurately if it is held in a horizontal position when the patient's eyes are also aligned horizontally, as in when the patient is sitting up. To position the marker, the user holds it in as horizontal as orientation as possible, aligns the marker with the patient's eye and then presses it against the eye so that the dye-coated axis tabs make the desired reference marks on the cornea. It is important for the corneal marker to be held as nearly level as possible during the marking process.
Examples of markers and tilt detectors are found in the prior art.
U.S. Pat. No. 6,217,596 (Farah) teaches and describes a corneal surface and pupillary cardinal axes marker having an inclinometer mounted on the frame.
U.S. Patent Application Publication 2008/00228210 (Davis) described prior art makers having level gauges or plumb bobs to indicate when the marker handle is being held in the horizontal position.
U.S. Pat. No. 4,739,761 teaches and describes a cornea marker that employs a rotating marker wheel to allow the cornea to be marked at selected locations.
Examples of ophthalmic measurement devices are also found in the prior art.
Nidek Co., Ltd. of Japan manufactures ophthalmic ultrasonic scanning devices capable of providing high quality imaging of the eye. This device is capable of performing various measurements of the eye, such as A-scans (biotmetry), B-scans (brightness), and corneal thickness measurements, as well as making IOL power calculations.
Traceys Technologies Corp. of Texas manufactures the iTrace device capable of ray tracing of the eye to perform corneal topography, auto-refraction, wave front analysis, pupillometry, and keratometry.
Bausch and Lomb of New York manufactures the Orbscan device capable of imaging the front and rear topography of the cornea, calculating the thickness and surface power of the cornea.
Alcon of Texas manufactures the Ora and system capable of performing corneal topography, real-time data capture and video display, and making lens power and axis recommendations.
Carl Zess Meditec AG of Germany manufactures the Callisto eye and Opmi Lumera devices that are capable of performing real-time topography measurements and overlaying visual aids onto a video image of the eyeiand or surgical microscope, wherein the visual aids indicate locations for incision or locations for IOL alignment.
It is an object of the present invention to provide instruments useful for marking the cornea for the insertion and alignment of a multifocal IOL while allowing the surgeon to double check the location of the corneal steep axis prior to insertion of the lens.
It is a further object of the present invention to provide a convenient and accurate way in which to assure that the corneal marker and the patient's eye are properly aligned to make an accurate measurement.
It is a further object of the present invention to provide a physical corneal marking system to augment and/or improve corneal measurement and analysis devices.
While the following describes a preferred embodiment or embodiments of the present invention, it is to be understood that this description is made by way of example only and is not intended to limit the scope of the present invention. It is expected that alterations and further modifications, as well as other and further applications of the principles of the present invention will occur to others skilled in the art to which the invention relates and, while differing from the foregoing, remain within the spirit and scope of the invention as herein described and claimed. Where means-plus-function clauses are used in the claims such language is intended to cover the structures described herein as performing the recited functions and not only structural equivalents but equivalent structures as well. For the purposes of the present disclosure, two structures that perform the same function within an environment described above may be equivalent structures.
These and further objects of the present invention will become more apparent upon considering the accompanying drawings in which:
Referring now to
A third marking tab 34 is formed integral with upper surface 18 and midway along blade 16 between first and second marking tabs 22, 24. Tab 34 has an upper marking edge 36. A fourth marking tab 38 having a lower marking edge 40 extends from lower surface 20 opposite third marking tab 34.
While the marking tabs 22, 24, 34 and 38 are shown in
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Attached to fork 48 is a combined gauge and keratometer assembly 50. As best seen in
Gauge ring 52 has a central circular aperture 56 formed therethrough. An inner toroidal marker ring 58 is rotatably fitted to gauge ring 52 through aperture 56. Ring 58 has a first right circular segment 60 held rotatably within the gauge ring 52 with first segment 60 extending above upper gauge ring surface 54. A reference mark 62 is engraved on ring 58.
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A keratometer ring 78 is attached to inner wall 80 of marker ring 58 by ring shaft 82. When axis marker 42 is placed on a patient's cornea, light from the operating microscope is directed through keratometer ring 78 and will highlight the general shape of any astigmatism in the cornea. This is not intended as a precise identification of the position of the steep axis of the cornea, but is intended to provide a backup indicator to confirm to the surgeon that the previously obtained keratometer readings were correct in identifying the steep axis.
In use, marking tabs 74, 76 are coated with a suitable dye and marker ring 58 is rotated to bring reference mark 62 in alignment with the scale scribed on surface 54 to coincide with the angle of the previously-measured steep axis. Non-rotating markers 70, 72 are then coated with a suitable dye. The instrument is then placed on the eye to bring one of the non-rotating tabs 70, 72 at the corner of the eye such that tabs 74, 76 are in alignment with the steep axis. Tabs 74, 76 are then pressed against the cornea to leave a pair of marks that allow the surgeon to align the IOL along the steep axis after insertion.
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It is to be understood that keratometer assembly 90 is assembled and functions generally in accordance with the foregoing descriptions of keratometer assemblies having rotating index rings and having marking tabs formed on the rotating and non-rotating portions of the assembly. In the view shown in
A tilt detector mount 100 is attached to handle 86 intermediate throat 88 and handle end 102.
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As tilt detector 104 is inclined with respect to the horizontal, various of the LEDs 106, 108, 110, 112, and 114 will sequentially light up to identify the orientation of tilt detector 104 and thereby handle 86. For example, if handle 86 is inclined to the right with keratometer assembly 90 being higher than handle end 102, LEDs 106, 108 will be illuminated. In similar fashion, if marker 84 is tilted such that keratometer assembly 90 is lower than handle end 102, LEDs 112, 114 will be illuminated. When center LED 110 is illuminated, handle 86 is in a horizontal position and reference marks 116. 118 are aligned vertically.
Tilt detector 104 is of the type that can also emit a characteristic sound when it is level and LED 110 is lit, or to warn when it is not level. Such detectors can thus provide both visual and auditory signals to indicate various stages of alignment.
Use of corneal marker 84 is enhanced when the patient's head is positioned so that the patient's eyes are horizontally level.
Referring now to
In use, headband 122 is placed around the patient's forehead as the patient is in a seated position. The patient's head is moved to produce a signal that the headband and, thereby, the patient's head are in a position to horizontally level the patient's eyes.
Corneal marker 84 is placed near the eye to be marked and handle 86 is inclined until a “level” signal is produced by tilt detector 104. When both tilt detectors 104, 124 produce level signals then keratometer assembly 90 is correctly oriented to mark the patient's eye.
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A communication pathway 142 extends between devices 132 and 136. Pathway 142 may consist of an electrically conductive wire and may also indicate a pathway created wirelessly by broadcast and receiving circuits provided in tilt detectors 132, 136.
Tilt detectors 132, 136 are adapted to communicate to each other and to indicate the degree to which each is inclined with respect to a selected reference. In the most common case, the selected reference will be the horizontal direction. Using the arrangement of
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Using such an arrangement, signal detector 154 can audibly, visually, or a combination thereof, indicate when tilt detectors 148, 152 are held in identical orientations with respect to a selected reference. As described above, communication passageway 156, 158 can be wired or wireless.
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It is also contemplated that a tilt detector constructed to withstand the sterilization process can be mounted in the handle itself.
If it is desired to keep patient distractions to a minimum when using the audible signal to verify alignment the signal can be set to broadcast to a set of headphones or an earpiece. The readings of both the corneal marker and the headband can be stored in a computer to make a full record of the patient's procedure for later review.
In use, the patient is first fitted with a headband constructed in accordance with the foregoing. Where there is a preset inclination, the patient is assisted to reach a head position where the preset is met as indicated by the signal generated by the tilt detector mounted on the headband. Next, a corneal marker, constructed as set forth herein, is selected, having a tilt detector with a preset inclination matching that of the headband. The corneal marker is adjusted to produce a signal confirming that the headband and the corneal marker are both aligned to the same preset inclination and the marking of the cornea is then carried out.
Where there is no preset inclination, the headband tilt detector and the corneal marker tilt detector are set to emit a signal when both are aligned to the same inclination. Once this signal is produced corneal marking can proceed. In this manner, even if the patient's head moves, an accurate reading will still be obtainable.
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Any number of marking blades can be used on any of the keratometers described herein, as desired. Individual marking blades on each of the keratometer assemblies may be inked or not inked to provide a desired number of reference marks on the cornea for surgical purposes.
While electronic levels 166, 210 have been described as providing visual indicators such as LEDs to indicate when the device is level it should be understood that audible signals can be produced as well, with different sounds indicating “left-right-level” attitudes, Thus, a surgeon can determine correct positioning of the corneal marker either visually, audibly, or both.
In another embodiment of the present invention, a more fully featured apparatus is provided for detecting the orientation of a patient's head in one, two or three directions, and in some instances, correlating the measured orientation of the patient's head with a marking instrument.
Referring now to
Frame 238 has a cross-bar 240 to which eyepieces 242, 244 are attached. A pair of temples 246, 248 are attached respectively to eyepieces 242, 244 respectively, allowing a patient to wear trial frame 238 in the same manner as a pair of eyeglasses.
In the example shown in
Referring now to
In use, a patient puts on frame 238 as though it were a pair of glasses and, during the patient's examination, the attitude of the patient's head with respect to the horizontal is adjusted by visually viewing spirit levels 250, or 256 and 258. When the patient's head is horizontally level, the steep angle can then be measured more accurately as described hereinabove.
As described above, an electronic level such as 166 or 210 can be substituted for the spirit levels in the foregoing embodiments.
It is possible to measure the orientation of a patient's head in more than one axis or direction. For example, it may be desirable to measure the horizontal inclination of the patient's head as has been discussed heretofore, and also measure the tilt forward or back of the patient's head. Likewise, it may also be desirable to measure the height of the patient's head above a given datum such as the floor or the chair seat in which the patient is seated. To do so would require a leveling device with broader or expanded capabilities.
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Use of leveling devices such as 268 and 278 allows the measurement of a patient's head orientation in one, two or three directions. For the purposes of this description, the x-axis is the measure of the horizontal attitude of the patient's head as described hereinabove. It is possible to construct electronic levels 268 and 278 such that the tilt of the patient's head perpendicular to the frame, that is, in a “nodding” position can be separately detected. For the purposes of this description this will be referred to as the z-axis. The distance of the patient's head may be measured along the y-axis.
Leveling devices 268 and 278 can then correlate this data to a visual or audio signal. For example, indicator light arrays 274,284 and 286 may be programmed to illuminate in a first selected color or make a first sound when a desired alignment of the patient's head has been reached along the x-axis, a second color or sound when the y-axis measurement reaches a desired value and a third sound or color with respect to measurements along the z-axis.
As an example, an indicator light flashing red can indicate the attitude of the patient's head in the x-axis direction while an indicator light flashing orange can indicate the position of the patient's head in the z-axis direction. It would then be possible for the examining physician to determine in what position the patient's head would be in the x-axis direction and subsequently in the y-axis direction.
It is also contemplated that the signals generated to activate the individually colored lights can be processed through an analog summarizer to produce an indicator or signal that the patient's head is aligned sufficiently in the x-, y-, and/or z-axis directions to meet the physician's criteria for accurate toric marking. The analog summarizer can be a computer program maintained on a computer or computer network with which the generated signals can be transmitted in a wired or wireless manner.
The summarizer can also be programmed onto a computer-readable card such as a CF card or SD card. A card reader can be built into a leveling device such as device 268 and later removed for data processing and storage.
Referring now to
The numeral 296 indicates a data point at which both the x- and y-axis measured values are ideal. At that point a green light signal is displayed and the physician knows that accurate toric marking can occur. In practice, data point 296 can represent a set of data points that, when achieved, allows marking to be carried out at an acceptable accuracy level.
Use of electronic levels 268 and 278 on both the toric marker and the trial frame can be made in much the same manner as described above in connection with
Signals generated by electronic levels 298 and 300 are transmitted to a signal processor 302 within which analyses are carried out by a signal summarizer programmed to respond by activating a series of visual or aural displays (or both) to inform the physician of the spatial orientation and positioning of each electronic level individually and to compare the values of each to determine when both are in a position within a selected data set to produce an acceptable marking of the patient's eye. As an example, red and orange signals, as described above, with provide cues to positional adjustments while a single green signal can indicate that the physician may proceed with the marking. The signals may be stored as part of the patient's records for later review.
While the foregoing examples have described particular types of frames suitable for use with mechanical or electronic attitude-detecting and measuring devices, such is use is not limited to any specific type of frame. Use of trial frames may be particularly apt because such frames can be used to measure other characteristics of a patient's eye in, for example, an operating room where larger and more conventional apparatus may not be appropriate.
The various types of mechanical and electronic attitude measuring devices uses in the foregoing examples are commonly and commercially available and are readily adaptable to be used to measure in one, two or three axes.
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The corneal marker 1020 has a receiver 1030 for receiving the signal(s) from the measurement device 1010. Preferably, the signal is wireless and the receiver 1030 has the form of an antenna (rf, near-field, Bluetooth, wi-fi, etc.). Alternatively, the receiver 1030 may have the form of a wired connection running between the measurement device 1010 and the corneal marker 1020.
The system 1000 further has one or more indicators 1040 capable of indicating data to the physician after the receiver 1030 has received the signal from the measurement device 1010. Preferably, the indicator 1040 has the form of a visual display, which displays the angle for marking the steep axis of the cornea. It will be appreciated that other forms of signaling the physician may be used, such as an audible voice or beeps, variable LED's, piezoelectric vibrations, all of which may indicate the proper angle for marking the steep axis of the cornea. Furthermore, the data indicated to the physician need not be limited solely to the steep axis of the cornea.
In a broad concept of the system 1000, the indicator 1040 may be located on or near the measurement device 1010 instead of on the corneal marker 1020 itself. In such an arrangement, data is sent from the measurement device 1010 to the indicator 1040. The measurement device 1010 and the marker 1020 may be capable of two-way transmission (which is indicated in
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The inventors have found that the novel corneal marking systems disclosed herein may reduce errors in placement of an IOL, and further the systems may serve as a low cost alternative to the expensive projection-type marking systems of the prior art, which are not capable of physically marking the eye.
Referring now to
Filing Document | Filing Date | Country | Kind |
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PCT/US16/27708 | 4/15/2016 | WO | 00 |
Number | Date | Country | |
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62148810 | Apr 2015 | US |