| Method and apparatus for determining intra ocular pressure of an eye -> Monitor Keywords |
|
|
 
Method and apparatus for determining intra ocular pressure of an eyeRelated Patent Categories: Surgery, Diagnostic Testing, Testing Aqueous Humor Pressure Or Related Condition, Measuring Force Required To Produce Standard Or Measured Eye Flattening (applanation)Method and apparatus for determining intra ocular pressure of an eye description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070173713, Method and apparatus for determining intra ocular pressure of an eye. Brief Patent Description - Full Patent Description - Patent Application Claims
REFERENCE TO RELATED APPLICATIONS [0001] This is a continuation-in-part of co-pending application Ser. No. 10/178,987, filed 25 Jun. 2002, entitled "Method and Apparatus for Examining an Eye". The aforementioned application is hereby incorporated herein by reference. TECHNICAL FIELD [0002] Eye examining instruments and methods. BACKGROUND [0003] Our previous U.S. Pat. Nos. 5,070,875, entitled "Applanation Tonometer Using Light Reflection To Determine Applanation Area Size", 6,179,779, entitled "Replaceable Prism System For Applanation Tonometer", 6,471,647, entitled "Method of Operating Tonometer", and 6,736,778, entitled "Replaceable Prism For Applanation Tonometer" suggest tonometers, tonometer operating methods, and tonometer prisms for measuring intra ocular pressure (IOP) of an eye. Our type of applanation tonometer has an actuator that presses a prism with a variable and determinable force against a cornea of an eye being examined while a source directs light to reflect from an applanation surface of the prism to a detector producing a detected light signal received by a microprocessor. [0004] Our experiments and experiences with working prototypes improving upon the disclosures of our issued patents and pending applications have led to several related discoveries. We have found that by changing and adding to the eye examining procedures instruments such as ours have made possible, we can calculate IOP more accurately. These changes involve not only improved eye examining methods, but also programming or otherwise structuring a tonometer to perform improved methods leading to information that has not previously been clinically available. SUMMARY [0005] The tonometers that are commonly used clinically have operated only during a diastolic phase and have measured only a diastolic intra ocular pressure (IOP). While our instrument accomplishes a diastolic IOP measurement, we have discovered that our instrument can also produce a useable signal during a systolic pulse occurring in an eye being examined. Upon exploring this, we found that a systolic phase signal from our instrument can be used to determine an ocular pulse pressure or a systolic IOP. This constitutes valuable additional information not obtainable with previous clinical tonometers. It provides a measure not only of diastolic IOP, but also of systolic IOP, and enables an average, weighted average, or mean IOP determination that more accurately represents the true or complete IOP experienced by the eye being examined. [0006] Other experiments with IOP signals attainable from our instrument have led to eye examining methods differing from our previous suggestions. We have found, for example, that t a prism pressing force variation range for IOP examining purposes can begin with an initial contact value and can change from that value through a predetermined range of change, rather than proceeding from a reference applanation area to a measurement applanation area. This method eliminates from the usable signal the variations in biomechanical properties of a specific cornea of an eye being examined, since such biomechanical variations are automatically involved in the initial contact value, which is subtracted or excluded from the usable signal. These corneal biomechanical properties, which vary from one eye to another include tear volume that supplies a surface tension force drawing a prism applanation surface into contact with the cornea and corneal properties that affect its elasticity or deformability, including corneal thickness and corneal curvature. All such variations affect the initial contact value and are thereby subtracted from an IOP determination that does not include or rely upon the initial contact value. [0007] Experience with systolic pulse signals produced by our instrument has led to discovery of other measurements available from examining an eye. We found that we can determine ocular blood flow derived from the departure of the detected light signal from the diastolic IOP during the systolic pulses. Moreover, we have found that we can determine a tonography measure from the way the detected light signal changes from a systolic pulse back to the diastolic phase. We can also determine tonography by measuring a preceding IOP; then pressing the prism against the eye with a predetermined force sufficient to raise the IOP for a predetermined interval; followed closely by determining a subsequent IOP. By doing this we can derive the tonography measure from the differences between the preceding and the subsequent IOP determinations. An ocular blood flow measurement and a tonographic measurement of the effectiveness of an eye's trabecular meshwork add significant and previously inaccessible diagnostic information of value to a clinician. [0008] Finally, to ensure that the additional information produced by our eye examining method and instrument is readily available to clinicians, we have made our instrument fast acting, compact, convenient, and objective in its operation. Besides producing much new information, our instrument automatically rejects false readings, and automatically requires concentric contact with a cornea at a proper orientation to attain an accurate reading. The programmed microprocessor in our instrument can preferably store, send, and receive information to perform all the required tasks and operations and to co-operate with computers and other information processing equipment. DRAWINGS [0009] FIG. 1 is a schematic view of a preferred embodiment of our improved tonometer, which is suitable for practicing our inventive eye examinations. [0010] FIG. 2 is a schematic diagram of a portion of the tonometer of FIG. 1 involving a prism applanating an eye, a light source, a detector, a microprocessor, and an output. [0011] FIGS. 3-8 are schematic graphs of detector signals produced pursuant to our inventive eye examinations. DETAILED DESCRIPTION [0012] Our eye examining method requires an instrument that can produce a signal representing intra ocular pressure (IOP) of an eye being examined. Such instruments are normally called tonometers, but our instrument and the ways it can be used produces information going beyond what can be expected of previous tonometers. Several variations of tonometers suitable for our purposes are described in our previous patents and applications. A presently preferred embodiment of such a tonometer 10 is schematically represented in FIGS. 1 and 2. Tonometer 10 preferably includes an actuator 15 pressing a prism 30 with a variable and determinable force against a cornea of an eye 40 while a light source 20 directs light to reflect from an applanation surface 31 of prism 30 to a detector 25. In response to received light, detector 25 produces a detected light signal that is electrical in form and is sent to and analyzed by microprocessor 50, which in turn controls actuator 15 for varying the force of prism 30 pressing against the eye 40 and for varying the energization of light source 20. Microprocessor 50 also preferably drives a display 51 and preferably communicates with output and input devices 52. [0013] The essential components of tonometer 10 include microprocessor 50, prism 30, some form of actuator 15, a light or radiation source 20, and a transducer or detector 25 receiving light or radiation reflected from applanation surface 31 and sending a corresponding electric signal to microprocessor 50. The precise working relationships among these essential components can be varied considerably, however, and the schematic illustrations of FIGS. 1 and 2 show only a presently preferred embodiment. [0014] Prism 30 is preferably replaceable and disposable so that it can be removed from prism holder 32 after each examination and replaced with a fresh prism. This ensures that infectious agents, including the possibility of prions, are not transmitted from one pair of eyes to another. [0015] Prism holder 32 is preferably mounted on arm 12, which is arranged to rotate or turn slightly around pivot 13. Since only a few millimeters of movement back and forth of prism 30 is required, as indicated by the double headed arrow, the rotational turning of arm 12 is slight. [0016] A counter balance 14 arranged on arm 11 is disposed at a suitable moment arm from pivot 13 to return prism holder arm 12 to a base position. Proper arrangement and balancing of arms 11 and 12 around pivot 13 can eliminate the need for any return spring, and can enable instrument 10 to operate in different orientations. The accurate counterbalancing of prism 30, as accomplished by element 14, allows tonometer 10 to be brought into a position in which prism 30 engages an eye without applying any pressure to the eye. [0017] Actuator 15 can be any of a variety of motors and other preferably electromagnetic prime movers. The preferred actuator schematically illustrated in FIG. 1 includes a coil 16 that is moveable relative to a permanent magnet 17, depending on the power supplied to coil 16. The relatively lighter coil 16 is preferably fixed to arm 12, and the relatively heavier permanent magnet 17 is preferably fixed to a body of instrument 10, because this reduces the rotating mass. It might also be possible to arrange permanent magnet 17 or coil 16 in the position of counter balance 14 to further reduce the rotational mass. Many other possibilities exist but for sake of conciseness and simplicity these have not been illustrated. [0018] Internal wiring within instrument 10 preferably connects a power supply (not shown) with microprocessor 50, which powers actuator 15, light source 20, and light detector 25. Microprocessor 50 preferably drives display 51 to display information directly to an instrument operator, and microprocessor 50 preferably has connections enabling it to receive and output information to and from other devices such as computers, keyboards, and number pads 52. Microprocessor 50 is preferably programmed to accomplish all the preferred operations of tonometer 10 and to calculate IOP on the signal information resulting from an eye examination. Continue reading about Method and apparatus for determining intra ocular pressure of an eye... Full patent description for Method and apparatus for determining intra ocular pressure of an eye Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this Method and apparatus for determining intra ocular pressure of an eye patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. Start now! - Receive info on patent apps like Method and apparatus for determining intra ocular pressure of an eye or other areas of interest. ### Previous Patent Application: Sensor with layered electrodes Next Patent Application: In vivo image display apparatus, receiving apparatus, and image display system using same and image display method thereof Industry Class: Surgery ### FreshPatents.com Support Thank you for viewing the Method and apparatus for determining intra ocular pressure of an eye patent info. IP-related news and info Results in 0.25042 seconds Other interesting Feshpatents.com categories: Novartis , Pfizer , Philips , Polaroid , Procter & Gamble , 174 |
 * Protect your Inventions * US Patent Office filing 
PATENT INFO |
|
