Refractive property measurement device, measurement tool, and refractive property measurement method
A refractive property measurement apparatus to measure refractive properties of an eye includes: a disk provided with a first pinhole and a second pinhole that transmit light rays while narrowing them; a light emitting unit that emits a first light ray and a second light ray from different positions on a surface of the disk, so that light rays passed through the first pinhole and the second pinhole enter the eye; and a processing unit determines refractive properties of the eye from information of positions on a retina of the eye where the first light ray having passed through the first pinhole and the second light ray having passed through the second pinhole reach. The first pinhole includes a first optical element that transmits the first light ray, and the second pinhole includes a second optical element that has transmission characteristics of transmitting the second light ray.
1. A refractive property measurement apparatus configured to measure refractive properties of an eye, the apparatus comprising:
a disk provided with a first aperture and a second aperture, the first aperture and the second aperture having a pinhole shape or a slit shape and being configured to transmit incident light rays while narrowing them;
a light emitting unit configured to emit a first light ray and a second light ray from different positions that are equally separated from the disk, on a plane parallel to a surface of the disk, so that the light rays having respectively passed through the first aperture and the second aperture enter the eye simultaneously; and
a processing unit configured to determine refractive properties of the eye from information of positions on a retina of the eye where the first light ray having passed through the first aperture and the second light ray having passed through the second aperture reach, wherein
the first aperture including a first optical element that has transmission characteristics of transmitting the first light ray but preventing the second light ray from passing therethrough,
the second aperture including a second optical element that has transmission characteristics of transmitting the second light ray but preventing the first light ray from passing therethrough,
the first light ray and the second light ray have different wavelength bands,
the first optical element is an optical filter in which a wavelength band is set so that the first light ray is transmitted but the second light ray is prevented from passing therethrough,
the second optical element is an optical filter in which a wavelength band is set so that the second light ray is transmitted but the first light ray is prevented from passing therethrough, and
the processing unit is configured to determine the refractive properties of the eye based on positions of images of the first light ray and the second light ray on a retina.
2. The refractive property measurement apparatus according to claim 1 , wherein the light emitting unit is configured such that at least one of the positions for emitting the first light ray and the second light ray is movable therebetween so that the positions for emitting the first light ray and the second light ray are able to be relatively displaced along an aperture arrangement direction of the first aperture and the second aperture.
3. The refractive property measurement apparatus according to claim 2 , wherein the processing unit is configured to calculate a refractive power of the eye by using a displacement amount between the positions for emitting the first light ray and the second light ray in a state in which positions in the aperture arrangement direction on the retina of the eye where the first light ray and the second light ray reach, coincide with each other.
4. The refractive property measurement apparatus according to claim 3 , further comprising:
a distance sensor that is configured to measure a distance between a surface for emitting the first light ray and the second light ray of the light emitting unit and the disk,
the processing unit being configured to calculate the refractive power of the eye from the distance measured by the distance sensor, the displacement amount, and a distance between centers of the first aperture and the second aperture.
5. The refractive property measurement apparatus according to claim 2 , further comprising:
a support for supporting the disk in such a manner that the aperture arrangement direction of the first aperture and the second aperture is rotatable.
6. The refractive property measurement apparatus according claim 1 , further comprising:
a support for supporting the disk in such a manner that the aperture arrangement direction of the first aperture and the second aperture is rotatable.
7. The refractive property measurement apparatus according to claim 6 , wherein the support is an eyeglasses frame, and the disk is mounted to a lens holder of the eyeglasses frame.
8. A measurement tool configured to be disposed between positions for emitting a first light ray and a second light ray, and an eye, in measuring refractive properties of the eye that receives the first light ray and the second light ray from forward, the tool comprising:
a disk provided with a first aperture and a second aperture, the first aperture and the second aperture having a pinhole shape or a slit shape and being configured to transmit the first light ray and the second light ray entering respective first aperture and second aperture simultaneously while narrowing the first light ray and the second light ray respectively, and to make the transmitted first light ray and second light ray reach a retina of the eye simultaneously; and
a support that fixes the disk in front of the eye, wherein
in order to enable distinguishing between positions on the retina of the eye where the first light ray having passed through the first aperture and the second light ray having passed through the second aperture reach,
the first aperture including a first optical element that has transmission characteristics of transmitting a wavelength band so that the first light ray can pass through but preventing the second light ray from passing therethrough, and
the second aperture including a second optical element that has transmission characteristics of transmitting a wavelength band so that the second light ray can pass through but preventing the first light ray from passing therethrough.
9. A refractive property measurement method for measuring refractive properties of an eye, the method comprising:
emitting a first light ray and a second light ray from different positions that are equally separated from a disk, on a plane parallel to a surface of the disk, so that incident light rays entering the disk enter the eye simultaneously by passing respectively through a first aperture and a second aperture provided to the disk, the first aperture and the second aperture having a pinhole shape or a slit shape and being configured to transmit the respective incident light rays simultaneously while narrowing them; and
determining the refractive properties of the eye from information of positions on a retina of the eye where the first light ray having passed through the first aperture and the second light ray having passed through the second aperture reach,
wherein the first aperture including a first optical element that has transmission characteristics of transmitting a wavelength band so that the first light ray can pass through but preventing the second light ray from passing therethrough,
the second aperture including a second optical element that has transmission characteristics of transmitting a wavelength band so that the second light ray can pass through but preventing the first light ray from passing therethrough.
10. The refractive property measurement method according to claim 9 , further comprising:
relatively displacing the positions for emitting the first light ray and the second light ray, therebetween, along an aperture arrangement direction of the first aperture and the second aperture, so that positions in the aperture arrangement direction on the retina of the eye where the first light ray having passed through the first aperture and the second light ray having passed through the second aperture reach, coincide with each other; and
calculating a refractive power of the eye by using an amount of the displacement along the aperture arrangement direction between the positions for emitting the first light ray and the second light ray in the state in which the positions in the aperture arrangement direction on the retina of the eye where the first light ray and the second light ray reach, coincide with each other.