KR20130107918A - Intraocular pressure measuring device and method for calculating intraocular pressure - Google Patents

Abstract

PURPOSE: An intraocular pressure measuring apparatus and an intraocular pressure calculating method are provided to accurately measure intraocular pressure by effectively correcting intraocular pressure measurement errors due to the biodynamic property of the cornea. CONSTITUTION: A photodiode (20) irradiates an applanation index light source to the cornea of an examinee. A photodetector (22) detects the applanation index light source reflected from the cornea with different intensity according to corneal deformities. A compressed air generating unit (30,32) deforms the cornea by spraying compressed air to the cornea of the examinee. A control unit (40) calculates intraocular pressure from the pressure of the compressed air and a signal of the applanation index light source. The control unit calculates the slope of an applanation signal peak from a signal waveform of the applanation index light source. The control unit corrects the pressure of the compressed air in an applanation state by using the slope of the calculated applanation signal peak. [Reference numerals] (40) Control unit

Description

Intraocular pressure measuring device and method for calculating intraocular pressure}

The present invention relates to an intraocular pressure measuring device and an intraocular pressure calculation method, and more particularly, to a non-contact intraocular pressure measurement capable of correcting intraocular pressure measurement errors caused by inherent biomechanical characteristics such as corneal thickness, viscosity, elasticity, and curvature. An apparatus and an intraocular pressure calculation method are provided.

Intraocular Pressure (IOP) is a pressure acting on the eye by an aqueous humor, a solution filling the cornea and the lens of the eye, and the normal intraocular pressure is generally about 10 to 21 mmHg. Normal-sized intraocular pressure maintains the shape and function of the eye, but abnormalities occur in the production and discharge of the waterproofing, and abnormally high intraocular pressure can damage the optic fiber layer of the retina or cause severe diseases such as glaucoma. As a result, vision may be lost. Therefore, accurate intraocular pressure measurement is very important for the early detection and treatment of eye diseases.

The tonometer for measuring the intraocular pressure may be classified into a contact type and a non-contact type according to whether a part of the device is in direct contact with the cornea. A typical contact tonometer is the Goldmann Applanation Tonometer (GAT), which is used when the cornea's surface reaches a flat state (pressure flatness) after pressing the center of the cornea with a probe with a built-in prism. Measure the force acting. GAT is used as a standard device for evaluating the accuracy of measured intraocular pressures with a clear measurement principle, but for intraocular pressure examinations, anesthetic anesthesia of the cornea is required, and there is a risk of infectious disease. Since a part of the device needs to remain in contact with the eye, it may cause fear and discomfort to the examinee, and an operation of an experienced ophthalmologist is required for accurate measurement.

Non-contact tonometer (NCT) injects compressed air into the cornea by solenoid drive, presses a certain area of the cornea (pressure) by air pressure, and the intraocular pressure from the time required for pressing pressure and the applied air pressure. To calculate. Since NCT does not require anesthesia and the test is performed instantaneously, inconvenience of the examinee can be minimized, operation is easy, and the accuracy of the measured intraocular pressure is excellent. 1 is a view for explaining the structure of a conventional non-contact tonometer. As shown in FIG. 1, a conventional non-contact tonometer includes an alignment state observation system, a flat state observation system, a compressed air generating unit, and a control unit. The alignment state observation system includes a gaze projection light source 12 that irradiates the gaze guided light that fixes the eye of the eye E, an alignment indicator light source 14 that irradiates the alignment light with the eye E, and the gaze A reflection mirror 16 for guiding the guided light in the direction of the eye to be examined E, and transmitting the alignment light, and a photodetecting element 18 for detecting the alignment light reflected from the eye to be examined E. FIG. The alignment light may also serve to illuminate the eye E. The flattening state observation system detects a photodiode 20 for irradiating a flattening indicator light source to the cornea of the eye to be examined, and a flattening indicator light source reflected by the cornea at different intensities depending on the deformation state of the cornea. It includes a photo detector 22. Here, the pressure smoothing indicator light source also serves as a Z-axis alignment indicator light source. The compressed air generating unit, a solenoid chamber 30 for generating compressed air, an injection nozzle 32 for injecting the compressed air generated in the solenoid chamber 30 to the eye to be examined E, and the injection nozzle 32 Pressure sensor 34 for detecting the air pressure of the compressed air is injected from. The control unit 40 controls the solenoid chamber 30 to adjust the supply of compressed air, deformed state of the cornea detected from the photodetector 22, and compressed air detected by the pressure sensor 34. Is inputted, and the intraocular pressure of the eye to be examined E is calculated.

Referring to the operation of the non-contact tonometer shown in FIG. 1, first, the gaze guided light (visible light) irradiated from the gaze projection light source 12 is formed on the retina of the eye E through the reflection mirror 16. The eye of the eye to be examined E is fixed. The alignment light irradiated from the alignment indicator light source 14 is imaged and reflected by the cornea of the eye to be examined E, and is detected by the photodetector element 18 via the reflection mirror 16. The inspector observes the detected alignment light and the position of the eye E, and the corneal center of the eye E is the injection nozzle 32 on the X and Y planes (the direction perpendicular to the advancing direction of the compressed air). The position of the eye E or the tonometer is adjusted so as to coincide with the center of the center, for example, the alignment light. Next, the pressurization indicator light source is irradiated from the photodiode 20 to the cornea of the eye E, and the pressurization indicator light source reflected from the cornea is detected by the photodetector 22. The inspector may adjust the distance between the injection nozzle 32 and the eye to be examined E on the Z axis according to the signal magnitude of the pressure smoothing indicator light source. Next, the controller 40 controls the solenoid chamber 30 to generate compressed air at an appropriate pressure, and injects the compressed air generated through the injection nozzle 32 into the eye to be examined E. FIG. Compressed air is generated by the piston movement inside the solenoid chamber 30, and as the piston moves, the pressure of the compressed air slowly increases and then decreases (indicated by the solid line in FIG. 2). The pressure of the compressed air is detected by the pressure sensor 34 and transmitted to the controller 40, and the pressure-compensating surface light source reflected by the cornea is also detected by the photodetector 22 and transmitted to the controller 40. The compressed air is injected into the cornea of the eye E to press and deform the cornea, and when the cornea is flattened (pressured), the intensity of the pressed surface light source detected by the photodetector 22 (Fig. 2 is indicated by a dotted line).

2 shows the pressure of the compressed air detected by the pressure sensor 34 and the pressure equalization detected by the photodetector 22 while the solenoid chamber 30 is driven to inject compressed air once into the eye E. FIG. This graph shows the intensity of the surface light source. As shown in FIG. 2, over time, the pressure of the compressed air (indicated by the solid line in FIG. 2) slowly increases, and the first convex cornea begins to deform and flatten at a certain time t1. In this case, the intensity (indicated by the dotted line in FIG. 2) of the pressure-reducing light source detected by the photodetector 22 also becomes maximum. Thereafter, as the air pressure continues to increase, the flattened cornea deforms concave, and the intensity of the flattened indicator light source also decreases. Then, as the air pressure decreases from the apex, the concave deformed cornea is flattened (second) again (t2), the intensity of the pressurized surface light source also increases, and at lower air pressures, the flattened cornea This convex deformation deteriorates the intensity of the pressurized surface light source. The controller 40 calculates the pressure values of the compressed air (PP1 and PP2, respectively) at the first flattening time point t1 and, if necessary, the second flattening time point t2, and calculates the pressure values of the compressed air and the standard. Intraocular pressure is calculated using a single regression equation created from intraocular pressure.

As described above, in the measurement of intraocular pressure, it is necessary to apply pressure to the cornea to pressurize the cornea. However, in addition to the actual intraocular pressure (water pressure that acts from inside to the outside of the cornea), the pressure required to compress the cornea is inherent to the eye's inherent body such as corneal thickness, viscosity, elasticity, and curvature. It also depends on the mechanical properties. In other words, the corneal tissue is a viscous and elastic biological tissue, which absorbs and attenuates the applied force, thereby exhibiting hysteresis. For example, when the cornea is thick, the intraocular pressure is measured higher than it is, and when the cornea is thin, the intraocular pressure is measured. Accordingly, a method of statistically quantifying the influence of corneal thickness and correcting intraocular pressure measured by contact method is also known (see US Patent 7,204,802). However, the actual intraocular pressure often depends on the hardness, viscosity, elasticity, curvature, and the like of the corneal tissue rather than the corneal thickness. Therefore, a method of canceling the hysteresis of the cornea by using the deformation of the cornea, which occurs during the pressure flattening of non-contact intraocular pressure measurement, is also known (see US Pat. No. 6,419,631). 3 is a view for explaining the intraocular pressure measurement method disclosed in US Patent No. 6,419,631. As shown in FIG. 3A, when compressed air applies pressure to the cornea C and the cornea C is first pressed, the applied air pressures F1 and IN are the actual intraocular pressure F3 and the cornea ( It is equal to the sum of the hysteresis F2 acting outwardly of C). Thereafter, when the air pressure increases, the cornea C becomes concave inward, and when the air pressure decreases past the highest point, the cornea C recovers its original shape, as shown in FIG. Becomes In this second pressing state, since the hysteresis F2 acts inwardly (inwardly) of the cornea C, the sum of the air pressures F1, OUT and the hysteresis F2 becomes equal to the actual intraocular pressure F3. Therefore, the actual intraocular pressure F3 is the average pressure Pavg of the air pressures F1, IN at the first pressing point, PP1 in FIG. 2, and the air pressures F1, OUT at the second pressing point, PP2 in FIG. 2. Is calculated. However, there is a temporal difference between the first and second pressure plates, and when compressed air is injected into the eye, the subject's position changes as the subject becomes embarrassed or in a moment's surprise, thereby reducing the accuracy of the intraocular pressure measurement. There is a problem.

Accordingly, it is an object of the present invention to provide a non-contact intraocular pressure measuring device and intraocular pressure calculation method capable of effectively correcting intraocular pressure measurement errors caused by biomechanical properties of the cornea. Another object of the present invention is to provide a non-contact intraocular pressure measuring device and intraocular pressure calculation method capable of more accurately measuring intraocular pressure.

In order to achieve the above object, the present invention, a photodiode for irradiating the pressure-enlarging indicator light source to the cornea of the eye to be examined; A photodetector for detecting a pressure equalizing indicator light source reflected by the cornea at different intensities according to the deformed state of the cornea; A compressed air generator for deforming the cornea by injecting compressed air into the eye; And a control unit for calculating intraocular pressure from the pressure of the compressed air and the signal of the pressure flattening indicator light source detected by the photodetector, wherein the control unit calculates the slope of the pressure signal peak from the signal waveform of the pressure flattening indicator light source. Using the inclination of the calculated peak signal peak, to provide a pressure measurement device characterized in that for correcting the compressed air pressure in the pressure flat state as a reference of the intraocular pressure calculation.

In addition, the present invention, by spraying compressed air to the cornea of the eye to be examined, deforming the cornea; Irradiating a pressure equalizing indicator light source onto the cornea of the eye, and detecting a signal (pressure signal) of the pressure equalizing indicator light source reflected from the cornea; And calculating the intraocular pressure from the pressure of the compressed air and the signal of the pressure flattening indicator light source, wherein the pressure of the pressure signal is calculated from the signal waveform of the pressure flattening indicator light source, and the calculated pressure signal is calculated. An intraocular pressure calculation method is provided by using a slope of a peak to correct a compressed air pressure in a pressurized state which is a reference for intraocular pressure calculation.

The non-contact intraocular pressure measuring apparatus according to the present invention can effectively correct intraocular pressure measurement errors caused by the biomechanical characteristics of the cornea, and more accurately measure intraocular pressure.

1 is a view for explaining the structure of a conventional non-contact tonometer.
2 is a graph showing the pressure of the compressed air and the intensity of the pressure-compensating surface light source during one injection of compressed air into the eye.
3 is a view for explaining a conventional intraocular pressure measurement method.
4 is a view for explaining the pressure of the compressed air and the deformation state of the cornea during intraocular pressure measurement.
Fig. 5 is a diagram showing a pressure signal signal detected by the photodetector when the cornea is brought into a flat state from the normal state in the intraocular pressure measurement according to the present invention.
6 is an enlarged graph showing detection signal waveforms of the photodetector for a time interval Δt at which pressure of compressed air is detected.
FIG. 7 is a diagram showing changes in the pressure signal signal waveform during the entire process of deterioration of the cornea in a normal state and restoring to its original shape in intraocular pressure measurement. FIG.
8 is a flow chart for explaining the intraocular pressure measurement and correction method according to the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

The mechanical configuration of the intraocular pressure measuring apparatus according to the present invention is the same as that of the conventional intraocular pressure measuring apparatus shown in FIG. 1, and the function of the controller 40 for correcting and calculating the intraocular pressure from the measured compressed air pressure and the pressure flat signal is not the same as that of the conventional apparatus. It is an improvement in comparison. 4 is a view for explaining the pressure of the compressed air and the deformation state of the cornea at the time of intraocular pressure measurement. As shown in FIG. 4, in the intraocular pressure measurement, when the compressed compressed air reaches the center of the cornea (A in FIG. 4), and when the pressure of the compressed air gradually increases, the corneal tissue starts to deform, and the deformation area thereof. This gradually expands (B in FIG. 4). Accordingly, the reflection area of the pressure equalizing indicator light source irradiated from the photodiode 20 (see FIG. 1) to the cornea increases, and the signal of the pressure equalizing indicator light source detected by the photodetector 22 (hereinafter, referred to as "pressure signal"). The intensity also increases (that is, the waveform of the pressure signal rises). When the compressed air pressure continues to increase and the corneal tissue is flattened (FIG. 4C), the pressure signal intensity detected by the photodetector 22 reaches a maximum (peak), thereby forming the first pressure point. Thereafter, as the pressure of the compressed air further increases, the corneal tissue continues to deform, concave inwardly (FIG. 4D), and the pressure signal strength of the photodetector 22 decreases. Next, when the pressure of the compressed air is reduced, the corneal tissue is restored to its original shape in the reverse order of the above, forming a second pressure point.

The present invention focuses on the fact that the slope of the pressure signal peak forming the two pressure points is different depending on the physical properties of the cornea. The present invention calculates the slope of pressure signal peaks from the pressure signal signal and calculates the pressure By using the slope of the signal peak, it is characterized in that the compressed air pressure in the pressure flat state as a reference for the intraocular pressure calculation is corrected. Accordingly, the intraocular pressure measuring apparatus according to the present invention includes a photodiode 20 for irradiating a pressure flattening indicator light source to the cornea of the eye to be examined, and a pressure flattening indicator light source reflected by the cornea at different intensities depending on the deformation state of the cornea. A photodetector 22 for detecting the pressure, compressed air generators 30 and 32 for deforming the cornea by injecting compressed air into the eye E, and the pressure of the compressed air and the photodetector 22 detected. And a control unit 40 for calculating the intraocular pressure from the signal of the pressure equalizing indicator light source.

With reference to FIG. 5, the intraocular pressure calculation method according to the first embodiment of the present invention will be described. Fig. 5 shows the pressure signal signal detected by the photodetector 22 when the cornea is pressed in the normal state (convex forward) in the intraocular pressure measurement according to the present invention. As shown in FIG. 5, while the compressed air pressure F gradually increases with time, the pressure signal A (t) detected by the photodetector 22 has almost no change to a certain point and then rises rapidly. Therefore, it becomes the maximum value A (t1) at the crimping time point t1, and has a form of a peak which rapidly decreases again. In FIG. 5, P (t1) is the compressed air pressure at time t1, and S (t1) is the slope of the pressure signal peak, indicating the speed of the cornea changing from convex to flat. If the central corneal thickness, corneal strength, corneal curvature, and the like, the greater the resistance to corneal deformation, the lower the overall slope (S (t1)), and conversely, the lower the stiffness of the corneal tissue, the total slope ( S (t1)) increases. Therefore, if the average rate of change (tilt) of the cornea having an average stiffness is Savg, the total slope S (t1) of the cornea having a stronger than average stiffness is smaller than Savg, and the entire cornea having a weaker stiffness than the average. The slope S (t1) is greater than Savg.

The slope S (t1) of the pressure signal peak may be calculated by various conventional methods. For example, as shown in FIG. 5, a straight line connecting the peaks t1 and A (t1) of the pressure signal signal peak from a point at which the pressure signal signal starts to increase (ta, where A (ta) = 0). Can be used as the slope S (t1) of the peak signal peak. In addition, if necessary, in calculating the slope S (t1) of the crimp signal peak, the region of the crimp signal value A (t) corresponding to less than 5% or 10% of the maximum value A (t1) of the crimp signal peak is excluded. By doing so, it is possible to eliminate the influence of noise near the base line. Alternatively, except for the baseline, in the time intervals ta to t1, a linear regression equation is created using the pressure signal A (t) data for time, and the slope of the written linear regression equation is squared. It can be used as the slope S (t1) of the signal peak.

The measured intraocular pressure is corrected using the average rate of change (S (t1)) of the flattened signal peaks thus calculated. Correction of the compressed air pressure P (t1) in the pressing state using the average rate of change S (t1) of the pressing signal peak may be performed in various ways. The compressed air pressure P (t1) may be corrected to be proportional, in a linear or otherwise manner, depending on the magnitude of the average rate of change S (t1) of the pressure signal peak. For example, the compressed air pressure P (t1) may be multiplied by the average rate of change S (t1) by a predetermined ratio or function to correct the compressed air pressure P (t1). Specifically, after compressed air is injected into the cornea of the eye to be examined, the position of the peak of the detected peak signal peak is t1, the pressure of the compressed air is P (t1), and the slope of the pressure signal is S (t1). And the slope of the platen signal of the cornea having an average stiffness or thickness is Savg (constant), according to the following equation 1, the difference between S (t1) and Savg is the inverse function of tangent as the inverse function of the compressed air pressure P (t1). ), The pressure P '(t1) is obtained. In Equation 1 below, Fn is a constant proportional to the size of compressed air injected into the cornea.

[Equation 1]

As can be seen from Equation 1 above, if the stiffness of the cornea to be examined is above the average, the compressed air pressure P '(t1) compensated as P' (t1) <P (t1) is greater than the stiffness. It is lowered to reflect the strength. On the other hand, if the stiffness of the cornea is below the average, the compensated compressed air pressure P '(t1) is high, reflecting that the stiffness is relatively weak as P'(t1)> P (t1). Since the pressure of the compressed air and the intraocular pressure calculated therefrom are directly proportional to each other, the intraocular pressure calculated from the compensated compressed air pressure P '(t1) becomes a value that offsets the error due to corneal stiffness. Here, the intraocular pressure value may be calculated by referring to a table measuring a standard intraocular pressure value corresponding to the corrected compressed air air pressure P ′ (t1) or a preset regression equation.

Another method (second embodiment) for correcting intraocular pressure using the relationship between corneal stiffness and the inclination signal slope is as follows. As shown in FIG. 5, until the corneal tissue starts to deform (ta), and until a certain area of the cornea deforms (tb), the pressure signal A (t) detected by the photodetector 22 is relative. Gradually increasing (change rate: s1), and then rapidly increasing until the critical point (t1) (change rate: s2). Here, the section in which the appreciation signal A (t) gradually increases and the section in which the appreciation signal is gradually increased can be appropriately separated as necessary, for example, a section in which the slope of the appreciation signal A (t) is obtained. It can be separated into two or three parts. FIG. 6 is a graph showing an enlarged detection signal waveform A of the photodetector 22 with respect to the time interval Δt at which the pressure of the compressed air is detected. The change amount A (ti) − of the detection signal in the i-th unit section is shown. From A (t (i-1)), the change rate A '(ti) and the average change rate s in the predetermined periods ta to tb can be obtained according to the following equation (2).

&Quot; (2) &quot;

Also, in each section, when the average rate of change (tilt) of the signal detected by the photodetector 22 is s1 and s2, according to Equation 3 below, from the time ta at which the deformation of the corneal tissue occurs, The average rate of change S (t1) up to t1) can be calculated. Where k = (time between ta and tb) / (time between ta and t1).

&Quot; (3) &quot;

If the central corneal thickness, corneal strength, corneal curvature, and the like are large, the larger the factors that resist corneal deformation, the smaller s1 and the smaller the total slope S (t1). On the contrary, as stiffness of corneal tissue is low, s1 increases and the overall slope S (t1) also increases. Using the slope S (t1) of the pressure signal signal peak thus calculated, the corrected compressed air air pressure P '(t1) can be obtained in the same manner as in the first embodiment, and the intraocular pressure can be calculated therefrom.

Another method (third embodiment) for correcting intraocular pressure using the relationship between corneal stiffness and the inclination signal slope is as follows. 7 shows that in the measurement of intraocular pressure, the pressure of the compressed air increases, and after the cornea becomes the first flattened state from the normal state, it is continuously deformed and concave, and the pressure of the compressed air decreases to form the original cornea. In the process of restoring to, the entirety of the pressure signal signal waveform (graph) forming the second pressure condition is shown. As shown in FIG. 7, if the slope s (t1) of the first pressure signal is lowered by the intraocular pressure acting outwardly and the stiffness (resistance) of the cornea, the point of flattening at the second pressure signal (peak, t2) The slope s (t2) from) to the time point tc of completion of corneal deformity is increased by intraocular pressure acting outwardly and the hysteresis of corneal tissue. In the cornea having an average stiffness, when the average change amount of the first pressure signal is S1avg and the average change amount of the second pressure signal with the average history is S2avg, s (t1) and S1avg according to Equation 4 below. The pressure P '(t1) whose corneal stiffness is corrected can be calculated. Further, according to Equation 5 below, the pressure P '(t2) whose corneal histories are corrected by s (t2) and S2avg can be calculated, and according to Equation 6, an average pressure P "(t) can be obtained. Can be.

&Quot; (4) &quot;

&Quot; (5) &quot;

&Quot; (6) &quot;

That is, the method of the third embodiment obtains, from two pressure points, two compressed air pressures P (t1) and P (t2) which form a pressure condition, and corrects them by the slope of the pressure signal peaks, thereby correcting them. Compressed air pressures P '(t1) and P' (t2), which are then averaged to obtain the average pressure P "(t), from which intraocular pressure is calculated, thereby more fully reflecting the physical properties of the cornea. Can be obtained.

Next, referring to FIGS. 1 and 5 to 8, a method of correcting intraocular pressure according to a third embodiment of the present invention will be described. 8 is a flow chart for explaining the intraocular pressure measurement and correction method according to the present invention. First, the compressed air is generated in the solenoid chamber 30 (S 12), and the generated compressed air is injected into the cornea of the eye E (S 14). At this time, the pressure (air pressure) of the compressed air is detected using the pressure sensor 34 (S 16), and the pressure flattening indicator light source reflected from the cornea of the eye E using the photodetector 22, that is, In step S18, the pressure signal is detected. The control unit 40 corrects and calculates intraocular pressure using the pressure of the compressed air and the pressure flat signal. Specifically, from the pressure signal signal graph, the time point at which the first pressure peak peak starts (ta), the time points t1 and t2 corresponding to the vertex of each pressure pressure peak, and the time point tc at which the second pressure pressure peak is completed (ended) are described. It detects (S20, S22, and S24). Next, the pressures P (t1) and P (t2) of the compressed air are calculated at the time points t1 and t2 corresponding to the vertices of the pressure peaks (S26). Next, in the interval from the start point ta of the first pressure peak to the peak t1 of the pressure peak, the average rate of change s (t1) of the pressure signal over time is calculated and the peak of the second pressure peak peak ( The average rate of change s (t2) from t2) to the time point tc at which the pressing peak is terminated is calculated (S28). Using the first average rate of change s (t1), the pressure P (t1) of the compressed air is corrected to calculate a pressure value P '(t1) in which corneal stiffness is corrected, and a second average rate of change s (t2)) is used to correct the compressed air pressure P (t2) to calculate the pressure value P '(t2) whose corneal stiffness is corrected (S30), and then the average value thereof (average air pressure value). , P ″ (t)) is calculated from the intraocular pressure corrected by the biomechanical characteristics of the cornea (S 32). The intraocular pressure correction according to the third embodiment of the present invention is described above with reference to FIG. Although the calculation method has been described, the intraocular pressure correction and calculation method according to the first and second embodiments of the present invention may be similarly performed.

In the intraocular pressure measuring device and the intraocular pressure correction method according to the present invention, after compressed air is injected into the cornea, and the flattening occurs from the time when the cornea is deformed by the compressed air, the cornea is further deformed, and the deformed cornea is deformed again. After peace, the pressure signal graph of the process of restoring to the original state is used to evaluate the physical characteristics (eg, relative strength) of the cornea being measured, and use this to correct the measured pressure value, ie intraocular pressure. Therefore, according to the intraocular pressure measuring apparatus and the intraocular pressure correction method according to the present invention, it is possible to obtain the correct intraocular pressure value by removing the influence of the cornea characteristics from the measured intraocular pressure.

Claims (5)

A photodiode for irradiating a pressure-enlarging indicator light source to the cornea of the eye to be examined;
A photodetector for detecting a pressure equalizing indicator light source reflected by the cornea at different intensities according to the deformed state of the cornea;
A compressed air generator for deforming the cornea by injecting compressed air into the eye; And
A control unit calculating an intraocular pressure from a pressure of the compressed air and a signal of a pressure equalizing indicator light source detected by the photo detector,
The control unit calculates the slope of the flattening signal peak from the signal waveform of the flattening indicator light source, and corrects the compressed air pressure in the flattening state as the reference for intraocular pressure calculation using the calculated slope of the flattening signal peak. Intraocular pressure measuring device characterized by the above-mentioned. The intraocular pressure measuring apparatus according to claim 1, wherein the compressed air pressure in the pressing state is corrected to be proportional to the slope of the pressing signal peak. Blowing compressed air into the cornea of the eye, thereby deforming the cornea;
Irradiating a pressure equalizing indicator light source onto the cornea of the eye, and detecting a signal (pressure signal) of the pressure equalizing indicator light source reflected from the cornea; And
In the intraocular pressure calculation method comprising the step of calculating the intraocular pressure from the pressure of the compressed air and the signal of the pressure equalizing surface light source,
Intraocular pressure is calculated by calculating the inclination of the flattening signal peak from the signal waveform of the flattening indicator light source, and using the calculated inclination of the flattening signal peak, correcting the compressed air pressure in the flattening state as a reference for intraocular pressure calculation. Output method. The method of claim 3, wherein the compressed air pressure in the pressing state is corrected to be proportional to the slope of the pressing signal peak. The intraocular pressure calculation method according to claim 3, wherein the inclination of the flattened signal peak is a slope of a straight line connecting the peaks of the flattened signal peak from the point where the flattened signal begins to increase.

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