JPH11276437A - Ophthalmological device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide relation between eye refracting power and form of a cornea in an easy-to-recognize way. SOLUTION: A cornea form computation part 53 obtains cornea surface refracting power data by measuring form of a cornea. An eye refracting power computation part 52 obtains objective eye refracting power data by measuring an objective eye refracting power. An analysis part 54 adds the objective eye refracting power data to the obtained cornea surface refracting power data to determine equivalent normal vision cornea surface refracting power data equivalent to take a subject eye as having a normal vision. Obtained data is displayed in a color display 56 as a color map.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ophthalmologic apparatus for obtaining eye information relating to the refractive power and corneal shape of an eye to be examined.

[0002]

2. Description of the Related Art The refractive power of an eye to be examined can be obtained by an objective eye refractive power measuring device. As this apparatus, there is known an apparatus which obtains an eye refractive power by projecting a measurement index on a fundus of a subject's eye and detecting a reflection index image from the fundus. The eye refractive power value is obtained as reflecting the information of the central region of the cornea being less than 3 mm.

The corneal surface shape of the eye to be examined can be obtained by a corneal curvature measuring device or a corneal shape analyzing device. As a corneal curvature measurement device, by detecting the position of the measurement index projected on the cornea, assuming the corneal shape as a toric surface,
It is known to obtain the curvature of the cornea in the strong meridian and weak meridian directions. This curvature value is also only information about the central region of the cornea of about 3 mm.

As a corneal shape analyzer, a large number of Placido ring indices projected on the corneal surface are image-processed,
It is known to determine the distribution of curvature over a wide range of the cornea. Further, the corneal curvature is expressed as a corneal surface refractive power. The following equation is generally used for this calculation. D = (ne−1) / r (1) where r is the corneal curvature, D is the refractive power, and ne is the converted refractive index of the cornea. Generally, ne = 1.3375 is widely used.

[0005]

The value measured by the eye-refractive-power measuring device indicates the amount of refraction (correction amount) required to bring the subject's eye into a state of emmetropia. The meaning of the converted refractive power is completely different. For this reason, the values measured by each measuring device are treated as separate values, and the mutual relationship is difficult to understand.

The present invention has been made in view of the above-mentioned prior art, and has as its technical object to provide an ophthalmologic apparatus capable of obtaining a relationship between an eye refractive power and a corneal shape in an easy-to-understand format.

[0007]

Means for Solving the Problems In order to solve the above problems, the present invention is characterized by having the following configuration.

(1) In an ophthalmologic apparatus for obtaining optometry information of an eye to be examined, refractive power data input means for inputting corneal surface refractive power data based on corneal shape measurement and objective eye refractive power data based on objective eye refractive power measurement. And refractive power calculating means for adding the objective eye refractive power data to the input corneal surface refractive power data to obtain equivalent emmetropic corneal surface refractive power data equivalent to estimating the eye to be examined as emmetropic; And a display means for displaying

(2) The display means of (1) comprises the equivalent emmetropic corneal surface refractive power data obtained by the refractive power calculating means, and the corneal surface refractive power data and objective eye inputted by the refractive power data input means. At least one of the refractive power data is graphically displayed on the same screen.

(3) In the ophthalmologic apparatus according to (1), the corneal surface refractive power data is refractive power distribution data of the corneal surface obtained from a corneal shape measured from near the center of the cornea to the eye to the peripheral region. The objective eye refractive power data is objective refractive power distribution data obtained by objectively measuring the refractive power of the subject's eye that changes along the periphery from the meridian direction and the center on the cornea, and the refractive power calculating means includes: The method is characterized in that distribution data of an equivalent emmetropic corneal surface refractive power is obtained by associating both refractive power distribution data on the cornea.

(4) In the ophthalmologic apparatus of (3), the corneal surface refractive power distribution data is a refractive power distribution at each corneal incident position when a light beam at infinity enters the cornea from the front direction of the eye to be examined. It is characterized in that it is determined based on Snell's law.

(5) In the ophthalmologic apparatus of (3), a curvature calculating means for converting the distribution data of the equivalent emmetropic corneal surface refractive power into a corneal curvature based on Snell's law, and a cornea obtained by the curvature calculating means. Second display means for graphically displaying the shape and the corneal shape obtained by the corneal shape measurement on the same screen.

(6) In the ophthalmologic apparatus of (3), residual astigmatism calculating means for obtaining distribution data of residual astigmatism excluding corneal surface astigmatism based on the equivalent emmetropic corneal surface refractive power distribution, and a second display for displaying the calculation result. And 3 display means.

(7) The ophthalmologic apparatus of (1) includes at least one of a corneal shape measuring means for obtaining the corneal surface refractive power data and an eye refractive power measuring means for obtaining objective eye refractive power data. It is characterized by.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic layout diagram of an optical system of an apparatus according to the present invention. The optical system is roughly classified into an eye refractive power measuring optical system, a fixation target optical system, and a corneal curvature measuring optical system.

(Eye Refractive Power Measuring Optical System) The eye refractive power measuring optical system 100 includes a slit projection optical system 1 and a slit image detecting optical system 10. The infrared light emitted from the light source 2 of the slit projection optical system 1 is reflected by the mirror 3 to illuminate the slit opening 4a of the rotating sector-4. Rotating sector-4
Is rotated by the motor 5. The slit light beam scanned by the rotation of the rotating sector-4 is reflected by the beam splitter 8 after passing through the projection lens 6 and the limiting aperture 7. Thereafter, the light passes through a beam splitter 9 having the optical axes of the fixation target optical system and the observation optical system coaxial, and is condensed in the vicinity of the cornea of the eye E, and then projected on the fundus. The light source 2 is located at a position conjugate with the vicinity of the cornea of the subject's eye with respect to the projection lens 6.

The slit image detecting optical system 10 has a main optical axis L1.
The light receiving lens 11 and the mirror 12 provided thereon, and the diaphragm 1 provided on the optical axis L3 reflected by the mirror 12
3 and a light receiving unit 14. The diaphragm 13 is arranged at a focal position on the rear side of the light receiving lens 11 via the mirror 12 (that is, located at a position conjugate with the fundus of the eye to be examined of the normal eye). As shown in FIG. 2, the light receiving section 14 is located at a position substantially conjugate with the cornea of the eye to be examined with respect to the light receiving lens 11 as shown in FIG.
Light receiving elements 15a to 15h. The light receiving elements 15a to 15f are located on a straight line passing through the center of the light receiving surface (optical axis L3), and the light receiving elements 15a and 15b, the light receiving elements 15c and 15d, and the light receiving elements 15e and 15f are respectively located at the center of the light receiving surface. It is provided so as to be symmetrical with respect to it.
The arrangement distances of the three pairs of light receiving elements are set so that the refractive power corresponding to each position in the meridian direction of the cornea can be detected (shown as an equivalent size on the cornea in FIG. 2). . On the other hand, the light receiving elements 15g and 15h are provided symmetrically on a straight line orthogonal to the light receiving elements 15a to 15f about the optical axis L3.

The eye refractive power measuring optical system 10 having such a configuration is described.
0 is a rotating mechanism 21 composed of a motor 20 and gears, etc.
, The slit illumination light source 2 of the slit projection optical system 1
The motor 5 rotates about the optical axis L2 and the light receiving section 14 rotates synchronously about the optical axis L3. In this embodiment, when the slit light beam is scanned by the slit opening 4a on the fundus of the eye to be examined having no astigmatism, the arrangement direction of the light receiving elements 15a to 15f is determined by the longitudinal direction of the slit received on the light receiving unit 14. The direction is set so as to be orthogonal to.

(Fixation target optical system) 30 is a fixation target optical system, 31 is a visible light source, 32 is a fixation target, and 33 is a light projecting lens. The light projecting lens 33 fogs the eye by moving in the optical axis direction. 34 is a beam splitter for making the optical axis of the observation optical system coaxial. The light source 31 is the fixation target 3
2 is illuminated, and the luminous flux from the fixation target 32 is
After passing through the beam splitter 34, the light is reflected by the beam splitter 9 and travels toward the eye E. The eye E fixes the fixation target 32.

(Cornea Curvature Measurement Optical System) The corneal curvature measurement optical system includes a curvature measurement target projection optical system 25 and a curvature measurement target detection optical system 35. Index projection optical system for curvature measurement 2
5 has the following configuration. Reference numeral 26 denotes a conical placid plate having an opening at the center. The placid plate 26 is formed with a ring pattern having a large number of light-transmitting portions and light-shielding portions concentrically around the optical axis L1. Reference numeral 27 denotes a plurality of illumination light sources such as LEDs. Illumination light emitted from the illumination light source 27 is reflected by a reflection plate 28 to illuminate the placido plate 26 almost uniformly from behind. The light beam of the ring pattern transmitted through the light transmitting portion of the placid plate 26 is projected on the cornea of the eye to be examined.

The curvature measuring index detecting optical system 35 includes a beam splitter 9, a beam splitter 34, and a photographing lens 37.
And a CCD camera 38. The corneal reflected luminous flux of the ring pattern projected by the curvature measuring index projection optical system 25 is reflected by the beam splitter 9 and the beam splitter 34, and then is photographed by the photographing lens 37 to the CCD camera 38.
A corneal reflection image of a ring pattern is formed on the surface of the image sensor. The curvature detection index detection optical system also serves as an observation optical system, and the eye E illuminated by an anterior segment illumination light source (not shown).
Is formed on the imaging element surface of the CCD camera 38,
The image is displayed on the TV monitor 39.

Next, the operation of the apparatus will be described with reference to the block diagram of the control system shown in FIG. First, measurement of eye refractive power and corneal curvature will be described.

When measuring the corneal curvature, the corneal curvature measurement mode is selected by the mode changeover switch 40. The examiner observes the anterior eye image of the eye E illuminated by an illumination light source (not shown) with the TV monitor 39 and performs alignment (alignment projects an index for alignment onto the cornea,
A well-known one that makes the corneal reflection bright point and the reticle have a predetermined relationship can be used. When the alignment is completed, a trigger signal is generated by a measurement start switch (not shown) to start the measurement.

The corneal shape calculation unit 53 includes a CCD camera 38
Performs image processing on the image photographed in step (1) to detect the edge of the placido ring image. Then, the corneal curvature is obtained by obtaining each edge position with respect to the corneal center at every predetermined angle (1 degree) step. The calculation of the corneal curvature can be performed as follows. As shown in FIG. 4, the image height i of the light source P at the optical axis distance D and height H from the cornea formed by the lens L on the two-dimensional detection surface by the lens L is represented by h. ´
Where m is the magnification of the optical system of the apparatus, the corneal curvature radius R can be obtained by the following equation. R = (2D / H) mh '

Further, the following calculation method of the corneal curvature can be adopted. The radius of curvature of the region where the j-th ring is projected on the cornea is Rj, the proportionality determined by the j-th ring height, the distance to the eye to be examined, and the imaging magnification is Kj,
Assuming that the image height on the imaging surface is hj, the above-mentioned relational expression is represented by Rj = Kj · hj. Here, by measuring in advance a plurality of model eyes having a known curvature covering the measurement range, a proportional constant Kj can be obtained as a device-specific value. Then, the curvature distribution can be obtained in a very short time (for details of the calculation of the corneal curvature, refer to Japanese Patent Application Laid-Open No. 7-124113). The obtained data of the corneal curvature is stored in the memory 55.

When measuring the eye refractive power (hereinafter referred to as objective eye refractive power), the measurement mode is switched to the eye refractive power measurement mode (when the continuous measurement mode is set, the eye refractive power measurement is automatically performed). Mode), eye refractive power measuring optical system 1
The measurement is performed according to 00. The eye-refractive-power calculator 52 obtains an objective eye-refractive-power distribution based on the phase difference between the output signals from the respective light receiving elements of the light receiving unit 14. First, a preliminary measurement is performed in the same way as the refractive power of the conventional phase difference method, and based on the result, the light projecting lens 33 of the fixation target optical system 30 is moved to fog the eye to be inspected. Thereafter, the center of the cornea in the meridian direction where the light receiving elements 15a to 15f are located is determined from the output signals of the light receiving elements 15g and 15h that change with the movement of the light of the slit image on the light receiving section 14. Next, each light receiving element 1 with respect to the center
From the phase differences of the output signals 5a to 15f, the refractive power at the cornea site corresponding to each light receiving element is obtained. By changing the refractive power for each meridian at each angle step while rotating the slit projection optical system 1 and the light receiving section 14 by 180 degrees around the optical axis at a predetermined angle (1 degree) step, it changes in the meridian direction. (Refer to Japanese Patent Application No. 8-283281 filed by the present applicant for details). The eye refractive power value here is a value based on a corneal vertex (the device can also output a refractive power value based on a spectacle lens wearing position). The obtained objective eye refractive power data is stored in the HDD 55a.
Alternatively, it is stored in the memory 55b.

When the measurement data of the objective refracting power and the corneal curvature is obtained as described above, the keyboard 58 or the mouse 57 is operated according to the instructions displayed on the color display 56 connected to the control unit 50. To start analysis. After converting the corneal curvature into the corneal surface refractive power, the analyzing unit 54 included in the control unit 50 executes an analysis program for representing a relationship between the corneal curvature and the objective eye refractive power.

The corneal curvature is determined by the corneal surface refractive power (Refractive P).
ower). The corneal surface refractive power is
This is the power when the light flux parallel to the normal of the corneal vertex is refracted by the cornea. For conversion from the corneal curvature, snell (sne)
ll). When converting the corneal curvature to the corneal surface refractive power, for the vicinity of the measurement optical axis (near the center of the cornea),
Even if the above-mentioned (Equation 1) is used, the error is small. But,
This can only be discussed in the vicinity of the measurement optical axis, and if applied to the periphery of the cornea beyond that, the reliability is poor. In other words, in order to treat the peripheral area of the cornea, it is assumed that the light incident on the cornea follows the refraction based on Snell's law, and the refractive power obtained by this becomes a refractive power that can be compared with the objective eye refractive power on the same scale. . As is well known, Snell's law (also called the law of refraction) is that when a light ray enters a refraction surface, the normal at the point of incidence of the light ray and the refraction light ray refracted at this point are on the same plane. And that the ratio of the sine between the normal and the refracted ray to the sine of the angle between the normal and the incident ray is constant. That is, the refractive indices on each side of the refraction surface are N and N ', and the angles formed by the incident light and the refracted light with the normal are i and i.
', Snell's law indicates that Nsini = N'sini'.

The calculation of the corneal surface refractive power using Snell's law will be described. Now, in FIG. 5, the corneal vertex T
And light parallel to a straight line passing through the center of curvature Oa is refracted at a point P on the cornea X away from the vertex of the cornea, and intersects the straight line TOa at a point f. Ra: corneal curvature at point P Rr: point P Θ: angle between normal direction at point P and incident light γ: angle between normal direction at point P and refracted light (distance is meter) The refractive power at the point P at this time can be obtained by the following equation. First, from the figure, θ is

(Equation 1) Becomes Γ is given by snell's law.

(Equation 2) Holds. From this, the angle α (the angle formed by the line segment hP and the line segment Pf), Rr, and the distance between the line segment hf shown in FIG.

(Equation 3) Becomes Separately, the distance of the line segment Th is

(Equation 4) Therefore, the distance from the corneal vertex to the point f is

(Equation 5) Becomes The refractive power in the cornea with the corneal refractive index n (= 1.376) is

(Equation 6) But the refractive power in the air is

(Equation 7) Becomes The corneal surface refractive power can be obtained by applying the above calculation to all the measurement areas (this calculation may be performed by the corneal shape calculation unit 53).

Next, for the corneal surface refractive power calculated as described above, the objective eye refractive power is represented by being converted into a refractive power equivalent to the corneal surface. That is, this is a value representing the refractive power required to make the eye to be examined emmetropic in the form of corneal surface refractive power (this is referred to as “equivalent emmetropic corneal surface refractive power” in this specification).

Here, the relationship between the objective eye refractive power and the corneal surface refractive power obtained from the corneal shape will be confirmed. The meaning of the value of the objective eye refractive power and the value of the refractive power obtained from the corneal shape are completely different as shown in FIG. The value of the refractive power obtained from the corneal shape determines the focal length and converts it into a refractive power. On the other hand, the objective eye refractive power measures the refractive power (correction amount) required to bring the eye into a state of normal vision. For example, if the corneal surface refractive power obtained from the corneal shape in the same area as the objective eye refractive power measurement area is 43.50D, and the objective eye refractive power measurement value is 0D, the corneal surface in this eye When the refractive power is 43.50D, it means that the optical system has an optical system that forms an image on the retina. Also,
The corneal surface refractive power obtained from the corneal shape is 43.50D,
If the objective eye refractive power is −2D, it indicates that in this eye, if the corneal surface refractive power is corrected by −2D (to 41.50D), an image is formed on the retina.

That is, in the measurement area of the objective eye refractive power, the value obtained by adding the measured value of the objective eye refractive power including the sign to the corneal surface refractive power obtained from the measurement of the corneal shape becomes the emmetropic state. Of the corneal surface. That is, this is the equivalent emmetropic corneal surface refractive power, and the equivalent emmetropic corneal surface refractive power =
It is expressed by corneal surface refractive power + objective eye refractive power.

Furthermore, the equivalent emmetropic corneal surface refractive power is converted into a corneal curvature using Snell's law. This conversion is shown in FIG.
Is obtained from the following two equations derived from the same concept as described above.

(Equation 8) Here, D is the equivalent emmetropic corneal surface refractive power, and Ra is the corneal curvature to be obtained.

The relationship between the value of the objective refractive power and the value obtained by measuring the corneal shape can be expressed in the form of a corneal surface by the equivalent emmetropic corneal surface refractive power obtained as described above and the corneal curvature obtained by converting the same. Therefore, it can be connected to the evaluation of the corneal surface shape. That is, the total refractive power of the eye is said to be mainly the sum of the corneal refractive power and the lens refractive power, but it is not easy to know the refractive power of the crystalline lens. Further, the axial length is added to the element of the refractive error. On the other hand, by expressing the refractive power of the eye in the above-described format, it is possible to replace the refractive error with the actual corneal surface shape without knowing unknowns such as the crystalline power and the axial axis. You can know the relationship with the shape.

When the equivalent refractive power of the corneal surface (and the converted corneal curvature) is obtained as described above, it is easy to visually compare the refractive power with the objective eye and the refractive power of the corneal surface. A graphic is displayed on the color display 56. FIG. 7 is an example of a color map display screen. The distribution of the corneal surface refractive power obtained from the corneal shape measurement is displayed on the display 61 at the upper right of the screen, the distribution of the objective eye refractive power is displayed on the display 62 at the upper left of the screen, and the display 63 on the lower part of the screen is displayed. The distribution of the emmetropic equivalent corneal surface refractive power is displayed as a color map. The display can be switched by a display switching key 60 at the lower right of the screen. As the display, the corneal curvature based on the measurement result of the corneal shape and the corneal curvature converted from the equivalent emmetropic corneal surface refractive power are respectively displayed as a color map display, a three-dimensional shape display, or a three-dimensional shape as a cross-sectional shape in a certain meridian direction. And can be displayed.

As described above, the relationship between the measurement result of the objective eye refractive power and the measurement result of the corneal shape and the relationship between the equivalent emmetropic corneal surface refractive power obtained therefrom are graphically displayed. In corrective surgery, it is possible to visually grasp how the corneal refractive power and the corneal shape before the operation change after the operation.

Further, when the execution of an analysis program for corneal correction surgery is instructed by operating a mouse or the like, the analysis unit 54 performs a corneal ablation based on the corneal curvature obtained by converting the equivalent refractive power of the corneal surface and the corneal curvature obtained by measuring the corneal shape. Calculate the amount. Hereinafter, this calculation method will be described.

As shown in FIGS. 8 and 9 (for the sake of simplicity, the figure shows a circular shape of the cornea and is shown as a cross section in a certain meridian direction). Then, the three-dimensional shape is calculated from the corneal curvature converted from the equivalent emmetropic corneal surface refractive power. Based on this shape and the three-dimensional shape calculated from the corneal curvature by the corneal shape measurement, the distribution of the difference in height in the region of the optical zone 70 is calculated based on the corneal vertex.

In the case of myopia correction, as shown in FIG. 8 (b), the central portion of the cornea is cut deep to increase the corneal curvature. Therefore, the three-dimensional shape calculated from the equivalent emmetropic corneal surface refractive power is translated downward by the maximum amount of the difference between the two three-dimensional shapes in the entire area of the optical zone 70. The three-dimensional shape after this movement becomes a corneal correction shape surface for emmetropia, and the distribution of the difference in the three-dimensional shape after movement calculated from the equivalent emmetropic corneal surface refractive power from the three-dimensional shape calculated by corneal shape measurement, This is information on the amount of resection. (The amount of change in the axial length after resection gives an error in the refractive power at most
0.25D, negligible. )

On the other hand, in the case of hyperopia correction, as shown in FIG. 9, the peripheral portion of the cornea is deeply resected to reduce the corneal curvature. In this case, the distribution of the difference between the two three-dimensional shapes in the entire area of the optical zone 70 becomes the information of the ablation amount as it is.

In both cases, when the maximum ablation amount exceeds the permissible amount of corneal ablation for the entire region of the optical zone 70, the region of the optical zone 70 is narrowed so as to be within the permissible amount. Correct the amount of resection. When the amount of ablation is negative due to corneal irregularities, the entire ablation is adjusted.

In calculating the ablation amount, the distribution of the ablation amount is directly obtained from the difference between the two three-dimensional shapes as described above, and the corneal ablation amount is calculated by various methods using the distribution information of the objective eye refractive power. Information can be obtained.

For example, a plurality of concentric regions are set from the central region to the peripheral region in the optical zone with respect to the curvature distribution obtained by measuring the corneal shape and the curvature distribution calculated from the equivalent corneal surface refractive power. The approximate curvature is calculated every time. From this, the three-dimensional shape is obtained to obtain the distribution of the corneal ablation amount (each boundary may be adjusted so as to be smoothly connected). In this case, the correction accuracy in the peripheral region can be improved with relatively simple laser beam control, compared to the case where the entire cut region of the optical zone is cut as a uniform spherical surface or toric surface.

Further, each of the corneal shape calculated from the corneal shape measurement and the corneal shape calculated from the equivalent emmetropic corneal surface refractive power is divided into a plurality of regions, which are ablated as aspherical shapes that can be expressed by an arithmetic expression. It is also possible to obtain quantity information.

The data of the corneal ablation amount calculated by the analysis unit 54 is stored in the HDD 55a or the memory 55b.
This data is obtained by operating the keyboard 58 and the like.
FD and communication port 59b by floppy drive 59a
Is transferred and input to a corneal surgery device 90 for ablating the cornea with excimer laser light via a communication cable connected to the device. The corneal surgery apparatus 90 determines the number of laser irradiation pulses and the irradiation power on each coordinate of the surgical cornea on the basis of the input corneal ablation data, and performs corneal surgery by controlling the laser irradiation accordingly.

In the above, an example has been shown in which the information on the objective eye refractive power distribution and the information on the corneal surface refractive power distribution (corneal curvature distribution) are used for corneal orthopedic surgery.

As the diagnosis of the eye to be examined, the information of the refractive power distribution of the objective eye and the information of the refractive power distribution of the corneal surface are compared to determine whether the astigmatic component of the eye to be examined is caused by the corneal shape or behind the corneal surface. It can be quantitatively and qualitatively grasped by distinguishing whether it is caused by an intraocular element from the eye to the retina. In other words, by subtracting the power at the center from the power at an arbitrary position of the equivalent emmetropic corneal surface refractive power described above,
The distribution of astigmatism components (residual astigmatism) in the eye up to the retina except for the corneal surface is calculated. This result is displayed on the display 56 in a color map as shown in FIG. From this, it is possible to determine the suitability of a contact lens used for refractive correction. For example, in the case of a subject eye with irregular astigmatism (this is known from information on the refractive power distribution of the objective eye), prescription of glasses or soft contact lenses cannot sufficiently correct vision,
If this irregular astigmatism is found to be mainly due to the corneal surface shape, correction with a hard contact lens can be recommended. Further, in the insertion of an intraocular lens for treating cataract, the information can be used as information for preventing astigmatism induction due to a tilt when the intraocular lens is inserted.

The embodiment described above can be variously modified. For example, the measuring means for obtaining the objective eye refractive power and the measuring means for obtaining the corneal shape are each configured as a separate measuring device, and each measurement data is inputted to the personal computer via the communication means, and the personal computer is used. The analysis may be performed on the side and the result may be displayed. In addition, the analysis may be performed on any one of the separately configured measurement devices.

In this embodiment, corneal shape measurement by Placido's ring projection has been described. However, all corneal shape measuring devices capable of obtaining a corneal curvature and a three-dimensional shape of the cornea, and all devices capable of obtaining an objective eye refractive power distribution. The present invention can be applied to the objective eye refractive power measuring device of the principle and method of the above.

[0050]

As described above, according to the present invention, the relationship between the eye refractive power and the corneal shape can be obtained in an easy-to-understand format. Thereby, appropriate diagnosis and refraction correction can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic arrangement of an optical system of an apparatus according to an embodiment.

FIG. 2 is a diagram illustrating an arrangement of light receiving elements included in a light receiving unit.

FIG. 3 is a diagram showing a schematic configuration of a control system of the apparatus of the present embodiment.

FIG. 4 is a diagram illustrating a method of calculating a corneal curvature.

FIG. 5 is a diagram showing a method for calculating a corneal surface refractive power.

FIG. 6 is a diagram showing a difference between a calculated value of refractive power obtained by corneal shape measurement and a measured value obtained by objective eye refractive power.

FIG. 7 is an example of a display screen of a color map.

FIG. 8 is a diagram illustrating a corneal ablation amount in the case of myopia correction.

FIG. 9 is a diagram illustrating a corneal ablation amount in the case of hyperopia correction.

[Explanation of symbols]

 25 Index Projection Optical System for Curvature Measurement 35 Index Detection Optical System for Curvature Measurement 50 Control Unit 52 Eye Refraction Calculation Unit 53 Corneal Shape Calculation Unit 54 Analysis Unit 56 Color Display 100 Eye Refraction Measurement Optical System

Claims (7)

[Claims] 1. An ophthalmologic apparatus for obtaining optometry information of an eye to be examined, a refractive power data inputting means for inputting corneal surface refractive power data by corneal shape measurement and objective eye refractive power data by objective eye refractive power measurement. A refractive power calculating means for adding the objective eye refractive power data to the input corneal surface refractive power data to obtain an equivalent emmetropic corneal surface refractive power data equivalent to estimating the subject's eye as emmetropia; and An ophthalmologic apparatus comprising: display means for displaying. 2. The display means according to claim 1, wherein said coronal surface refractive power data obtained by said refractive power calculating means, corneal surface refractive power data and objective refraction inputted by said refractive power data input means. At least one of the force data
An ophthalmologic apparatus characterized by displaying graphics on the same screen. 3. The ophthalmologic apparatus according to claim 1, wherein the corneal surface refractive power data is refractive power distribution data of a corneal surface obtained from a corneal shape measured from around a center of a cornea to a subject to a peripheral region, The objective eye refractive power data is objective refractive power distribution data obtained by objectively measuring the refractive power of the eye to be examined, which varies along the meridian direction and the center from the center of the cornea to the periphery. An ophthalmologic apparatus, wherein distribution data of an equivalent emmetropic corneal surface refractive power is obtained by associating the above two refractive power distribution data. 4. The ophthalmologic apparatus according to claim 3, wherein the corneal surface refractive power distribution data includes a refractive power distribution at each corneal incident position when a light beam at infinity is incident on the cornea from the front direction of the subject's eye. An ophthalmic apparatus characterized by being determined based on the law of 5. The ophthalmologic apparatus according to claim 3, wherein a curvature calculating means for converting the distribution data of the equivalent normal corneal surface refractive power into a corneal curvature based on Snell's law, and a corneal shape obtained by the curvature calculating means. An ophthalmologic apparatus, comprising: a second display unit for graphically displaying the corneal shape obtained by the corneal shape measurement on the same screen. 6. The ophthalmologic apparatus according to claim 3, wherein residual astigmatism calculating means for obtaining distribution data of residual astigmatism excluding corneal surface astigmatism based on the equivalent emmetropic corneal surface refractive power distribution, and a third displaying the calculation result. An ophthalmologic apparatus comprising: a display unit. 7. The ophthalmologic apparatus according to claim 1, further comprising at least one of a corneal shape measuring unit for obtaining the corneal surface refractive power data and an eye refractive power measuring unit for obtaining objective eye refractive power data. Ophthalmic equipment characterized.