Abstract:
A biometry device to facilitate immersion biometry allowing the biometrist to perform the study without having to hold a device onto the patient&#39;s eye and without the need for a local topical anesthetic. The device consists of a mask or goggles that fit over the patient&#39;s eyes. The mask/goggles can have a single fluid chamber covering both eyes or two fluid chambers, one to cover each eye. Transducers are mounted in the goggle, one opposite each eye. The transducers are mounted in a housing that allows each one to be manipulated so that it is axially aligned with the eye under examination.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    Intraocular lenses were first implanted following cataract surgery by Harold Ridley in England in 1949. Since then there have been enormous advances in both the lens design and the surgical procedure for removal of cataracts. The modem surgical procedure is done under topical anesthesia, the cataract is removed by phacoemulsification and a foldable replacement lens is inserted into the eye through a 3.5 mm incision. The surgical procedure takes approximately 10-15 minutes and the patient goes home in less than an hour.  
           [0002]    An appropriate intraocular lens of the correct power has to be selected for each individual eye undergoing surgery. In the early days of lens implantation this was based upon the patient&#39;s refraction. Later ultrasound biometry was developed to further refine the true accuracy of lens power selection. In the majority of cases this is performed by placing a transducer on the surface of the cornea and recording by means of a printer the peaks of the sound wave as it strikes the posterior inner surface of the eye, the posterior and anterior surfaces of the human lens and the anterior and posterior surfaces of the cornea. From these tracings the axial length of the eye, the length of the vitreous cavity, the lens thickness and the depth of the anterior chamber can be measured. One or a combination of these measurements are fed into a computer along with measurements of the average of the radii of curvature of the cornea at both its steepest and flattest meridians, the “K” Readings.” The biometrist then enters into the computer a constant for the particular lens design (the “A” constant) and selects one of several available formulas to calculate the lens power. The computer printer then produces a list of lenses for selection with the anticipated postoperative refraction for each lens power. The surgeon then selects from the computer printout the appropriate lens to implant.  
           [0003]    This technique of biometry is by far the most common currently performed method of biometry and requires a skilled and experienced technician. The technician has to place the transducer onto the cornea with the least amount of corneal distortion or flattening and do this consistently from eye to eye. The most critical measurement entered into the formula is the axial length of the eye. A 1 mm indentation of the cornea shortens the axial length, and can result in a postoperative refractive error of 3 diopters leaving the patient severely myopic. Accurate biometry is therefore vital to get good uncorrected visions postoperatively. Many surgeons have not, until recently, evaluated the uncorrected outcomes of their surgery.  
           [0004]    In the late 90&#39;s a multifocal intraocular lens was introduced into the market, the Array™ by Allergan. This lens focuses the light on the retina of the eye both for distance and near simultaneously. The brain has to select the appropriate image it wishes to recognize. This lens allows the patient to see at distance and near; however because the light in focus is divided between a distance and near target, contrast is lost and there is significant glare. The development of this lens, however, has made the eye surgeon conscious of the importance of the accuracy of the preoperative biometry. Since the objective of implanting the lens is to enable the patient to live without glasses. As explained above, this examination entails utilizing sound waves to measure the length of the eye, this measurement plus the radii of curvature of the cornea at its steepest and flattest meridians is applied to one of several formulas to determine what lens power should be implanted into the eye to give a predetermined preoperative refraction. In most cases this selection of the lens power for an eye would result in the patient being able to see well as distance without glasses, i.e. emmetropia.  
           [0005]    The introduction of the Array™ intraocular lens should enable patients to see at distance and near without glasses. In order to achieve this goal the surgeon has to have excellent uncorrected vision and the importance of accurate biometry has become very apparent to the surgeons implanting this multifocal lens.  
           [0006]    Accurate biometry can be achieved by two methods, one utilizing the standard biometry equipment modified to allow the measurement to be made through a fluid or water bath (immersion biometry). The second method is by means of the IOL Master™ from Zeiss which utilizes partial coherent laser interferometry to define the various intraocular measurements. Immersion biometry has not been popular with surgeons and their technicians because a chamber has to be placed onto the eye and filled with fluid before the biometry measurement can be made. The techniques for doing this have been cumbersome and in many cases required the patients to lie flat on their backs and the technician to be skilled. The great advantage of this technique however is that there is not corneal distortion and therefore very accurate lens power estimations care obtained. The IOL Master™ from Zeiss is also accurate because it is user friendly and does not involve contact with the cornea. This instrument does, however, have two disadvantages. First, it cannot be used on patients with dense cataracts and secondly is expensive. The immersion technique, if it could be simplified, is therefore the preferable technique. The basis of this patent is a simplification of the technique of immersion biometry.  
         BRIEF SUMMARY OF THE INVENTION  
         [0007]    The invention provides a device to facilitate immersion biometry allowing the biometrist to perform the study without having to hold a device onto the patient&#39;s eye and without the need for a local topical anesthetic. The device renders the examination much more acceptable and more comfortable to the patient than other immersion biometry techniques.  
           [0008]    The device consists of a mask or goggles that fit over the patient&#39;s eyes. The mask/goggles can have a single fluid chamber covering both eyes or two fluid chambers, one to cover each eye. The mask, designed to be watertight, is held in place by an adjustable strap that goes around the head. The mask is connected by flexible tubes to a container or bag of fluid, usually water or saline.  
           [0009]    The container is connected by one tube if there is one chamber in the goggle or two tubes if there are two chambers. The fluid container is located beneath the goggle. The chamber(s) of the goggle is (are) filled with saline by raising the bag above the level of the goggle. When the goggle chambers are full of saline, a clamp is closed across the tube connecting the container to the goggle and the bag lowered to a level beneath the goggle. There is then a “waterbath” between the eye and the front of the goggle through which sound waves can pass without there being any contact between the goggle fitted with a transducer and the eye.  
           [0010]    Two transducers are mounted in the goggle, one opposite each eye. The transducers are mounted in a housing that allows each one to be manipulated so that it is axially aligned with the eye under examination. Each eye is examined separately by re-routing the cables connecting each transducer to the ultrasound scanner.  
           [0011]    Upon completion of the scans, the clamp preventing the drainage of saline from the goggle is opened and the saline is drained back into the bag.  
           [0012]    The parallel-sided transducer is mounted in the goggle such that its alignment can be moved to align with the optical axis of the eye. This is essential in order to take a reading. The adjustable alignment can be achieved by a ball-and-socket arrangement or XY movements. The transducer has to be movable in and out to a distance range in which measurements can be taken. The housing or opening for the transducer has to be watertight, which can be achieved by the use of a circular flexible membrane with a hole in its center or with O rings. The transducer can then slide into or out of the mask or goggles and rotate onto the optical axis by asking the patient to look at a fixation light on the end of the transducer. During the manipulation, the examiner would watch the biometer screen; a measurement would only be recorded when the transducer distance and alignment with the eye is correct. The cables from each transducer would be activated alternately by a cable switch such that one eye could be examined after the other.  
           [0013]    The mask or goggle design has a hole(s) in its roof to allow the air to escape from the mask as it fills with saline or water. The floor of the mask tapers or funnels into the outflow tube so that when the clamp or lock is opened the saline will pool in the funnel during its drainage from the mask, leaving little or no residue.  
           [0014]    The mask is constructed such that it has windows through which the biometrist can observe the tip of the transducer to correctly position it relative to the eye. Alternatively the mask may utilize a goggle, similar to a swimming goggle, with a transducer mount  
           [0015]    The mask will fit all faces and have an adjustable headband to fit around or around and over the head.  
           [0016]    A system can be designed such that there are two bags: the input bag and the drain bag. The goggles are filled by lifting the input bag above the level of the goggles after opening a clamp or a stopcock. After the goggles are full, the clamp is closed and the bag with a reservoir of remaining solution is lowered to rest on the patient&#39;s lap. Solution remaining in the bag can be used for future examinations. After completing the biometry, a second clamp or stopcock is opened and the fluid drained from the goggle.  
           [0017]    Utilizing the system with cleaning the goggles between patients, multiple examinations can be performed using the same input bag of fluid. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]    For a more complete understanding of the present invention, reference is now made to the following descriptions taken in conjunction with the accompanying drawing, in which:  
         [0019]    [0019]FIG. 1 is a perspective frontal view of one embodiment of the biometry goggles;  
         [0020]    [0020]FIG. 2 is a perspective top view of the biometry goggles of FIG. 1;  
         [0021]    [0021]FIG. 3 a  is a perspective frontal view of one embodiment of the biometry with viewing windows;  
         [0022]    [0022]FIG. 3 b  is a perspective frontal view of an alternative embodiment of the biometry goggles with viewing windows;  
         [0023]    [0023]FIG. 4 is sectional side view of one embodiment of a fluid chamber with a ball-and-socket system;  
         [0024]    [0024]FIG. 5 is a sectional side view of the fluid chamber of FIG. 4 further illustrating the ball-and-socket system;  
         [0025]    [0025]FIG. 6 is a top view of the fluid chamber of FIG. 5;  
         [0026]    [0026]FIG. 7 is schematic top view illustrating an alternative embodiment of the invention with an X-Y system;  
         [0027]    [0027]FIG. 8 is a schematic illustrating an embodiment of the invention utilizing a single fluid container; and  
         [0028]    [0028]FIG. 9 is a schematic illustrating an embodiment of the invention utilizing a first fluid container and a second fluid container. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0029]    Referring to FIG. 1, a pair of biometry goggles  10  is shown worn about a patient&#39;s head. In the displayed embodiment, a pair of fluid chambers or goggles  11 ,  12  are shown placed over the patient&#39;s eyes. The fluid chambers  11 ,  12  are interconnected to one another through a fluid chamber connector  16 . This fluid chamber connector may be a flexible strap, rigid piece of material connecting the fluid chambers  11 ,  12 , such as plastic, or the fluid chamber connector may be made of any material allowing for adjustable positioning of the fluid chambers  11 ,  12  over the patient&#39;s eyes. Furthermore, the fluid chamber connector may be integrally molded with the fluid chambers  11 ,  12 . The fluid chambers  11 ,  12  are secured to the patient&#39;s head preferably with a strap  15  that is flexible and adjustable. In other embodiments, other materials and other configurations may utilized to secure the fluid chambers  11 ,  12  over the patient&#39;s eyes. Although the biometry goggles  10  are shown in FIG. 1 with two fluid chambers  11 ,  12 , an alternate embodiment of the invention includes a single fluid chamber. This single fluid chamber may be a chamber that covers one or both eyes of a patient.  
         [0030]    The fluid chambers  11 ,  12  have a fluid chamber base  18 ,  19 . The fluid chamber base  18 ,  19  interfaces with the surface of the patient&#39;s head. The fluid chamber base  11 ,  19  may be configured concavely to follow the curvature of a person&#39;s head. The fluid chamber base  18 ,  19  provides a water tight seal around the patient&#39;s eye. The fluid chamber base may include a rubber seal, a sponge foam, or other material to form a seal between the fluid chamber base and the patient&#39;s head, for example material that is ordinarily used in swimming goggles to form a seal around the eyes.  
         [0031]    In one embodiment the fluid chambers  11 ,  12  of the biometry goggles  10  have a viewing panel/transducer support frame  14  and one or more viewing panels  13 . The viewing panel  13  are fitted within the support frame  14  and the fluid chamber base  18 ,  19 . The viewing panels allow the device operator to see the patient&#39;s eye and to view the positioning of the transducer  16 . Alternatively, the fluid chamber may be made with a single viewing panel or goggle with the viewing panel or goggle having a central transducer mount. The viewing panels or goggle are preferably made from a polycarbonate material. However, other material may be used that allowing viewing through the material, for example, certain plastics and glass.  
         [0032]    Referring now to FIG. 2, a perspective top view of the biometry goggles of FIG. 1 is shown. The fluid chambers  11 ,  12  have transducers  16 ,  17  that are mounted in the fluid chambers. The fluid chambers  11 ,  12  have a transducer mount  20 ,  21 . The transducer mount  20 ,  21  houses the transducer  16 ,  17 . The transducer mount  20 ,  21  allows for movement of the transducer  16 ,  17  for biometry analysis of the eye.  
         [0033]    [0033]FIGS. 3 a  and  3   b  illustrate other embodiments of the biometry goggles  10  showing different configurations of viewing panels.  
         [0034]    [0034]FIG. 4 is a sectional side view of one embodiment of a fluid chamber  21 . In this embodiment, the transducer mount  20  utilizes a ball  22  for rotatable movement of the transducer  16 . A transducer lead  23  is connected to the transducer  16 . The transducer  16  is held within the rotatable ball  22 . The fluid chamber  21  when placed over the patient&#39;s eye forms a “liquid-tight” fluid reservoir  24 . The transducer  16  when taking biometry readings is immersed in the fluid reservoir.  
         [0035]    Referring now to FIG. 5, a sectional side view of the fluid chamber of FIG. 4 further illustrates the ball-and-socket system. The ball  22  of the ball and socket system holds the transducer  16  in place. The transducer  16 , in addition to being rotatably positionable, may be moved anteriorly away from the surface of the eye  31  and posteriorly towards the surface of the eye  31 . The ball  22  may be configured in separate sections such that the ball is removable from the transducer mount  20 . In this configuration, the ball includes an anterior portion  24  and posterior portion  25  which are held to a main body  26  of the ball  22  by set screws or other fixation means. Seals  32 ,  31  may be used to provide a water-tight seal for the transducer. The seals  31  may be replaced by removing the anterior or posterior portions  24 ,  26  and exchanging the seal for a new seal.  
         [0036]    [0036]FIG. 6 is a top view of the fluid chamber of FIG. 5. The transducer  16  is placed in a central hole of the ball  22 . In this embodiment, a rubber seal  16  is utilized to retain the transducer  16  in the ball  22  and allow the transducer to move anteriorly and posteriorly from the eye while providing a water-tight seal.  
         [0037]    In FIG. 7 an alternate embodiment of the transducer mount  20  is shown. In this embodiment the transducer mount  20 , includes an X-Y visual axis alignment mechanism instead of the rotating ball system. The X-Y mechanism allows the operator to examine the eye in the straight-ahead position adjusting the transducer up or down and side to sided to correspond to the visual axis of the eye.  
         [0038]    Referring now to FIG. 8, a schematic illustration depicts an embodiment of the biometry goggles  10  utilizing a single fluid reservoir  43  for providing a fluid  44  to the fluid chambers  11 ,  12 . A patient wearing the biometry goggles generally lies in the supine position. The fluid reservoir  43  is raised to a level above the biometry goggles  10 . A fluid flow regulator  41 , such as a clamp or stopcock, controls the release of the fluid  44  from the fluid container  43 . A fluid transport carrier  40 , such as tubing, attaches to the biometry goggles to fluid valves  46  and  47 . The fluid flow regulator  41  when opened releases the fluid  44  from the fluid reservoir  43  which is then dispensed into the fluid chambers  11 ,  12 . When fluid chambers  11 ,  12  are full of fluid, the fluid flow regulator  41  is closed and the fluid reservoir  43  lowered to a level beneath the goggles  10 . The fluid in the fluid chambers  11 ,  12  provides a “waterbath” between the eye and the transducers  16 ,  17 . Sound waves can pass through the fluid without any contact between the eye and the transducers  16 ,  17 . After biometric readings have been taken, the fluid in the fluid chambers  11 ,  12  may be released back to the fluid reservoir  43 .  
         [0039]    The biometry goggles  10  may include air inlet/outlet valves  18 ,  19  to release air in the fluid chambers  11 ,  12  when filing the chambers with the fluid  44  and to intake air when releasing the fluid back into the fluid reservoir  43 .  
         [0040]    Transducer lead lines  23 ,  27  may be connected to a control switch  42  allowing for selective biometric reading for an individual transducer, or both, allowing the operator to take independent readings of the right eye or the left eye, or both concurrently. The lead lines  23 ,  27  continue through the control switch  42  to a plug  45  for the biometric reading machine.  
         [0041]    Referring to FIG. 9, a schematic illustration of an embodiment of the invention is shown where the biometry goggles  10  utilize a first fluid reservoir  44  and a second fluid reservoir  51 . In this embodiment, a first fluid reservoir  55  containing a fluid  44  is release by way of a first flow control regulator  52  into to the biometry goggles  10 . This operation is similar to the operation of the embodiment of FIG. 8. Instead of the fluid being released back into the same reservoir, when biometric readings are completed, the fluid is released into a second fluid reservoir  51 . The release into the second fluid reservoir is controlled by a second flow control regulator  53 . In this embodiment, each fluid chamber includes two fluid valves  56 ,  57 , and  58 ,  59 . A first set of fluid valves  56 ,  58  are used to fill the fluid chambers  11 ,  12  from a first fluid transport carrier  55 , and a second set of fluid valves  57 ,  58  are used to release the fluid into a second fluid transport carrier  60 .  
         [0042]    Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.