JP2021112369A - Lens transmission spectrum estimation system and lens transmission spectrum estimation method - Google Patents

Abstract

To provide a crystalline lens transmission spectrum estimation system for simply acquiring optical density of a crystalline lens without depending on a sense of an object person.SOLUTION: An estimation system 10 includes an image data actual measurement unit 20 that measures brightness of a plurality of images having wavelengths differing from each other and formed by the crystalline lens as actual measurement brightness for each wavelength and measures sizes of the images as actual measurement sizes for each wavelength. The estimation system 10 acquires estimated optical density in a predetermined wavelength range by using the actual measurement brightness and the actual measurement sizes and, on the basis of the estimated optical density, calculates a transmission factor of the crystalline lens in the predetermined wavelength range as a transmission spectrum of the crystalline lens.SELECTED DRAWING: Figure 4

Description

The present invention relates to a transmission spectrum estimation system for the crystalline lens and a transmission spectrum estimation method for the crystalline lens.

It is known that the optical density of the crystalline lens of the human eye (hereinafter, simply referred to as the crystalline lens) increases with aging. Age-related changes in the optical density of the crystalline lens are thought to affect visual functions such as how to perceive color and non-visual functions such as adjustment of the daily rhythm. Therefore, various techniques for easily measuring the optical density of the crystalline lens according to the age have been proposed.

For example, Patent Document 1 discloses a device for evaluating the glare of a light source felt by a measurement target person (hereinafter, may be simply referred to as a target person). In the apparatus disclosed in Patent Document 1, the transmission characteristics of the crystalline lens of the subject's eye are acquired, and the transmission characteristics of the subject's eye are obtained based on the spectrum of the light emitted from the light source and the transmission characteristics acquired as described above. Calculate the spectrum of light reaching the retina. After that, the apparatus disclosed in Patent Document 1 calculates and outputs an index representing the glare of the light source felt by the subject based on the above-mentioned light spectrum.

Patent Document 2 discloses an apparatus for simply measuring the spectral sensitivity characteristics of the human eye. In the apparatus disclosed in Patent Document 2, a plurality of devices irradiated from a light source for measurement are emitted based on the spectral luminosity efficiency of the average observer classified according to the type such as age group and progression of symptoms. For different colored lights, the average observer of the same classification derives the light intensity ratio between the colored lights that is perceived as having equal brightness. Subsequently, in the apparatus disclosed in Patent Document 2, when the subject observes the light in which the light intensity ratio is changed with the different colored light and receives a report that the light intensity is perceived as equal brightness, the calculation is performed as described above. The subjects are sorted into the corresponding classifications based on the classification correspondence data prepared in advance from the light intensity ratio between the colored lights. After that, the spectral sensitivity characteristics of the subject are estimated from the sorted classification.

Japanese Unexamined Patent Publication No. 2008-093131 Japanese Unexamined Patent Publication No. 2008-237492

However, conventional devices such as the devices disclosed in Patent Documents 1 and 2 described above depend on the subject's sensation and response when determining the optical density of the crystalline lens according to the age, and an error due to the sensation may occur. In some cases, the optical density including the above and the like is calculated, or when it is difficult for the subject to respond, the measurement cannot be performed and the optical density of the crystalline lens cannot be obtained.

The present invention has been made in view of the above circumstances, and provides a transmission spectrum estimation system for the crystalline lens and a transmission spectrum estimation method for the crystalline lens in order to easily obtain the optical density of the crystalline lens without relying on the sense of the subject. do.

The present invention includes the following aspects.
[1] The brightness of a plurality of images having different wavelengths formed by the crystal body is measured as the measured brightness for each of the plurality of different wavelengths, and the size of the image is measured as the measured size for each of the plurality of different wavelengths. The ratio of the actually measured brightness of each of the plurality of different wavelengths to the reference brightness obtained in advance for each of the plurality of different wavelengths, and the said of each of the plurality of different wavelengths. An optical density calculation unit that calculates the measured optical density at each of the plurality of different wavelengths of the crystal body based on the ratio of the measured size to the reference size obtained in advance for each of the plurality of different wavelengths. An optical density that satisfies a predetermined condition for the measured optical density at each of the plurality of different wavelengths and is estimated as an estimated optical density by using a known optical density obtained in advance for a predetermined wavelength range including the plurality of different wavelengths. Transmission spectrum of a crystal body including an estimation unit and a spectrum calculation unit that calculates the transmission rate of the crystal body in the predetermined wavelength range as a transmission spectrum of the crystal body based on the estimated optical density in the predetermined wavelength range. Estimate system.
[2] The known optical density obtained in advance for the predetermined wavelength range is calculated based on the crystalline lens age of the crystalline lens for each wavelength within the predetermined wavelength range and a predetermined coefficient according to the crystalline lens age. , [1]. The transmission spectrum estimation system for the crystalline lens.
[3] The transmission spectrum estimation system for a crystalline lens according to [1] or [2], wherein the image is an image formed by reflection on a surface of the crystalline lens adjacent to the vitreous body.
[4] The transmission spectrum of the crystalline lens according to any one of [1] to [3], wherein the plurality of different wavelengths include 600 nm and at least one wavelength in the wavelength band of 400 nm or more and less than 600 nm. Estimate system.
[5] The transmission spectrum estimation system for a crystalline lens according to any one of [1] to [4], further comprising a light source for irradiating the crystalline lens with light having a plurality of wavelengths different from each other.
[6] The crystalline lens according to any one of [1] to [5], wherein a gaze object is arranged behind the crystalline lens in the direction of incidence of the plurality of light having different wavelengths on the crystalline lens. Transmission spectrum estimation system.
[7] The brightness of a plurality of images having different wavelengths formed by the crystal body is measured as the measured brightness for each of the plurality of different wavelengths, and the size of the image is measured as the measured size for each of the plurality of different wavelengths. Then, the ratio of the measured brightness of each of the plurality of different wavelengths to the reference brightness obtained in advance for each of the plurality of different wavelengths, and the measured size and the plurality of each of the plurality of different wavelengths. Based on the ratio to the reference size obtained in advance for each of the different wavelengths, the measured optical density of the crystal body at each of the plurality of different wavelengths is calculated, and the measured optical density at each of the plurality of different wavelengths is calculated. The difference between the optical density and the predetermined known optical density containing the plurality of different wavelengths among the known optical densities obtained in advance for the predetermined wavelength range containing the plurality of different wavelengths is the smallest. The known optical density is estimated as an estimated optical density, and the transmission rate of the crystal body in the predetermined wavelength range is calculated as the transmission spectrum of the crystal body based on the estimated optical density in the predetermined wavelength range. A method for estimating the transmission spectrum of a crystalline body.

According to the above-mentioned inspection lighting device and inspection device, the inspector can decompose and visually recognize the hue of the specularly reflected light from the inspection target portion regardless of the shape of the inspection target portion.

FIG. 1 is a schematic view of a transmission spectrum estimation system (estimation system) for a crystalline lens according to an embodiment of the present invention. FIG. 2 is a side view for explaining the principle of forming a Purkinje image in the estimation system shown in FIG. FIG. 3 is a schematic diagram for explaining the brightness and magnitude of the Purkinje image in the estimation system shown in FIG. FIG. 4 is a schematic view different from FIG. 1 of the estimation system of one embodiment according to the present invention. FIG. 5 is a block diagram relating to an optical density calculation unit, an optical density estimation unit, and a spectrum calculation unit of the estimation system shown in FIG. FIG. 6 is a schematic view of a part of the transmittance spectrum estimation system in the example. FIG. 7 is a photograph of the Purkinje image obtained in the example. FIG. 8 is a graph showing the distribution of the measured optical densities of the crystalline lenses of a plurality of subjects calculated in the examples. FIG. 9 is a graph showing the estimated optical density estimated for each age group in the examples. FIG. 10 is a graph showing the transmission spectrum for each age group estimated in the examples.

Hereinafter, preferred embodiments of the lens transmission spectrum estimation system and the lens transmission spectrum estimation method according to the present invention will be described with reference to the drawings.

As shown in FIG. 1, the transmission spectrum estimation system 10 of the crystalline lens of the embodiment to which the present invention is applied (hereinafter, may be simply referred to as the estimation system 10) includes an image data measurement unit 20 and an optical density calculation unit 50. An optical density estimation unit 60 and a spectrum calculation unit 70 are provided.

The image data measurement unit 20 measures the brightness and magnitude of the plurality of Purkinje images (images) 120 having different wavelengths formed by the crystalline lens 310 as the measured brightness and the measured size for each of the plurality of different wavelengths. The Purkinje image 120 is a reflection image by the surface of the cornea or the crystalline lens.

In general, there are a plurality of types of Purkinje image 120. The plurality of types of Purkinje images include, for example, the first Purkinje image 121 to the fourth Purkinje image 124, as shown in FIG. The first Purkinje image 121 is a reflected light 202 when the incident light 200 incident on the subject's eye (not shown) is reflected on the surface 302a on the front side of the incident light 200 in the cornea 302 of the subject's eye. It is an image formed by. The second Purkinje image 122 is an image formed by the reflected light 204 when the transmitted light 205 transmitted through the surface 302a of the cornea 302 is reflected by the surface 302b on the back side of the incident light 200 in the incident direction in the cornea 302. .. The first Pulkiner image 121 and the second Pulkiner image 122 are not inverted in the vertical direction and the horizontal direction orthogonal to the vertical direction with respect to the projected image 130, and are oriented in the same direction. In FIG. 2, the first Purkinje image 121 and the second Purkinje image 122 are illustrated so as to overlap each other.

The third Purkinje image 123 is an image formed by the reflected light 206 when the transmitted light 210 transmitted through the surface 302b of the cornea 302 is reflected by the surface 310a on the front side of the incident light 200 in the incident direction in the crystalline lens 310. .. The third Purkinje image 123 is not inverted in the vertical direction and the horizontal direction orthogonal to the vertical direction with respect to the projected image 130, and is oriented in the same direction as each other. The fourth Purkinje image 124 is an image formed by the reflected light 208 when the transmitted light 215 transmitted through the surface 310a of the crystalline lens 310 is reflected by the surface 310b on the inner side of the incident light 200 in the incident direction in the crystalline lens 310. .. The fourth Purkinje image 124 is inverted in the vertical direction and the horizontal direction orthogonal to the vertical direction with respect to the projected image 130, and is opposite to each other.

The image data measurement unit 20 measures the brightness and magnitude of the fourth Purkinje image 124. As shown in FIG. 2, the reflected light 204 is inclined with respect to the reflected light 202 because it is refracted through the surface 302a after being emitted from the surface 302b of the cornea 302. However, since the cornea 302 is very thin (for example, thinner than the maximum thickness of the crystalline lens 310), it can be said that the reflected lights 202 and 204 are substantially parallel to each other. On the other hand, the reflected light 208 is refracted every time it is emitted from the surface 310b of the crystalline lens 310 and then sequentially passes through the surface 310a and the surfaces 302b and 302a of the cornea 302. Therefore, the reflected light 208 is more inclined with respect to the reflected light 202 than the reflected lights 202, 204, and 206. That is, the angle θ4 formed by the reflected light 208 (hereinafter, simply referred to as the reflected light 208) emitted from the surface 302a of the cornea 302 and the incident light 200 emitted the other reflected light 202, 204 and the surface 302a of the cornea 302. Each of the reflected light 206 is larger than each of the angles (not shown) formed by the incident light 200.

The crystalline lens 310 is adjacent to the vitreous 330. The vitreous 330 is located behind the crystalline lens 310 in the incident direction of the incident light 200. That is, the fourth Purkinje image 124 is an image formed by reflection on the surface 310b of the surface of the crystalline lens 310 adjacent to the vitreous 330.

As shown in FIG. 1, the image data measurement unit 20 includes, for example, a light source 22, an optical fiber 24, a molding filter 28, and an image pickup camera 30. The light source 22 emits multicolored light containing at least a plurality of wavelengths different from each other. The input end of the optical fiber 24 is connected to the exit portion of the light source 22. The light source 22 includes, for example, a xenon lamp (not shown) capable of lighting white light as multicolored light, and a bandpass filter. As the bandpass filter rotates inside the light source 22, a plurality of different wavelengths λ1, ..., λm light IL1, ..., ILm among the multicolored lights of the xenon lamp pass through the bandpass filter transmission. It is input to the optical fiber 24 and emitted from the output end 25 of the optical fiber 24. m represents a plurality of numbers having different wavelengths from each other, and is a natural number of 2 or more. The wavelengths λ1, ..., λm preferably include 600 nm and at least one wavelength within the wavelength band of 400 nm or more and less than 600 nm.

The molding filter 28 has a posture in which the plate surface is substantially orthogonal to the optical axis (broken line in FIG. 1) of the optical IL1, ..., ILm emitted from the output end 25 of the optical fiber 24, and the optical fiber 24 It is provided at a position away from the output end 25. A hole having a diameter of, for example, about 3 mm is formed in the central portion of the molding filter 28. The optical IL1, ..., ILm pass through the holes formed in the molding filter 28 and are molded into a predetermined shape. The light IL1, ..., ILm is applied to the eye 350 to be measured, which is arranged on the path.

The imaging camera 30 receives the reflected light RL1, ..., RLm reflected by the surface 310b of the crystalline lens 310 in the eye 350, and receives the fourth Purkinje image 124-1 for each wavelength λ1, ..., λm. ..., 124-m is imaged. Information about the fourth Purkinje image 124-1, ..., 124-m captured by the imaging camera 30 is transmitted to a computer 40 such as a personal computer via a cable.

The computer 40 includes an optical density calculation unit 50, an optical density estimation unit 60, and a spectrum calculation unit 70. However, in FIG. 1 and FIG. 3 described later, the optical density calculation unit 50, the optical density estimation unit 60, the spectrum calculation unit 70, and the crystalline lens 310 are omitted.

The optical density calculation unit 50 measures the brightness of the fourth Purkinje image 124-1, ..., 124-m formed by the crystalline lens 310 and captured by the image pickup camera 30 as the measured brightness. Further, the optical density calculation unit 50 measures the size of the fourth Purkinje image 124-1, ..., 124-m as the measured size. For example, the measured brightness of the fourth Purkinje image 124-1, ..., 124-m is the average value of the brightness within each range of the fourth Purkinje image 124-1, ..., 124-m. be. Similarly, the measured size of the fourth Purkinje image 124-1, ..., 124-m is a position corresponding to 1/2 of the vertical axis when the maximum value of the vertical axis of the profile illustrated in FIG. 3 is 1. Is the width of the profile (distance at the measured position), which is the so-called full width at half maximum (FWHM) of the profile illustrated in FIG. Further, the actually measured size of the fourth Purkinje image 124-1, ..., 124-m corresponds to ^{1 / e 2} of the vertical axis when the maximum value of the vertical axis of the profile illustrated in FIG. 3 is 1. It may be the width of the profile of the position to be performed (distance of the measured position).

The optical density calculation unit 50 determines the measured brightness and the measured size of the fourth Pulkiner image 124-1, ..., 124-m of the eye whose optical density is substantially constant regardless of the wavelengths λ1, ..., λm. Information on the reference brightness and the reference size calculated by the same calculation method as in each of the above is obtained in advance. The optical density calculation unit 50 is based on the ratio of the measured brightness of each of the wavelengths λ1, ..., λm to the reference brightness, and the ratio of the measured size of each of the wavelengths λ1, ..., λm to the reference size. _{Then, the measured optical densities AD media} (λ1), ..., AD _media (λm) at each of the wavelengths λ1, ..., λm are calculated.

The optical density calculation unit 50 has a plurality of known optics having wavelengths λ1, ..., λm among a plurality of known optical density distributions obtained in advance for a predetermined wavelength range including wavelengths λ1, ..., λm. Information on the concentration FD _media (λ1), ..., FD _media (λm) is obtained in advance. The predetermined wavelength range is, for example, the wavelength band of visible light, which is a range of 380 nm or more and 780 nm or less. The plurality of known optical density distributions are, for example, optical density distributions according to the age of the subject. The optical density calculating unit 50, among the plurality of known optical density _{FD media (λk),} the measured optical density _{AD media (λk)} known optical density difference is smallest between the _{FD media (λk)} the estimated optical density _{ED media} ( Estimated as λ). k is a natural number from 1 to m.

The spectrum calculation unit 70 calculates the transmittance T (λk) of the crystalline lens 310 in the predetermined wavelength range as the transmission spectrum T (λ) of the crystalline lens 310 based on _{the estimated optical density ED media (λ) in the predetermined wavelength range.}

The optical density calculation unit 50, the optical density estimation unit 60, and the spectrum calculation unit 70 are configured as programs that execute the respective processing contents, and are built in the computer 40.

The transmission spectrum estimation method of the crystalline lens of one embodiment to which the present invention is applied includes the first to fifth steps described below.

In the first step, using the image data measurement unit 20, the optical density in a predetermined wavelength range (referred to as absolute optical density to distinguish it from the known optical density) ZD _media (λk) is the wavelength λ1, ... , A substantially constant (optical density is known) simulated eye is set at the position of the eye 350 in FIG. 1 regardless of λm. The incident light ILk is applied to the eye 350. Subsequently, the image pickup camera 30 receives the reflected light RLk and images the fourth Purkinje image 124-k. Here, the fourth Purkinje image 124-k of the simulated eye is referred to as the Purkinje image Ref [124-k]. Information about the Purkinje image Ref [124-k] captured by the image pickup camera 30 is transmitted to the optical density calculation unit 50 of the computer 40.

In the optical density calculation unit 50, the Pulkinje image Ref [124-k] is represented as a profile plotted on a graph in which the horizontal axis is the measured position and the vertical axis is the brightness as shown in FIG. 3, and the maximum value and full width at half maximum of the profile are represented. , And let each be the reference luminance FL (λk) and the reference size FW (λk). The actually measured position of the profile described above is represented by the number of pixels of the imaging camera 30. The brightness of the profile described above is represented by the brightness or gradation of each pixel of the imaging camera 30. Each pixel of the image pickup camera 30 and the size at the time of actual measurement are calibrated, and the brightness of each pixel of the image pickup camera 30, that is, the gradation and the brightness of the light incident on the image pickup camera 30 are also calibrated. The obtained reference luminance FL (λk) and reference size FW (λk) are stored in the storage unit 45 of the computer 40, an arbitrary database, or the like.

Next, in the second step, the brightness of a plurality of fourth Pulkinje images 124-k having different wavelengths λk formed by the crystalline lens 310 is measured as the measured brightness AL (λk) for each of the plurality of wavelengths λk, and the fourth step is performed. The size of the Purkinje image 124-k is measured as the measured size AW (λk) for each of a plurality of wavelengths λk.

More specifically, the subject's eye is set at the position of the eye 360 in FIG. 4, and the gaze object 90 is placed in the field of view of the eye 360 as shown in FIG. That is, in the estimation system 10, the gaze object 90 is arranged behind the crystalline lens 310 in the incident direction of the incident light (a plurality of lights having different wavelengths) ILk.

Subsequently, using the image data measurement unit 20, the molding filter 28 is operated in the same manner as in the first step, and the incident light ILk is irradiated to the eye 350. The image pickup camera 30 receives the reflected light RLk and images the fourth Purkinje image 124-k. Here, the fourth Purkinje image 124-k of the subject's eye is referred to as the Purkinje image Meas [124-k]. Information about the Purkinje image Meas [124-k] captured by the imaging camera 30 is transmitted to the optical density calculation unit 50 of the computer 40.

Subsequently, as shown in FIG. 3, the Purkinje image Meas [124-k] is represented as a profile plotted on a graph in which the horizontal axis is the measured position and the vertical axis is the brightness, and the maximum value and the full width at half maximum of the profile are obtained. Let each be the measured brightness AL (λk) and the measured size AW (λk).

Next, in the third step, as shown in FIG. 5, in the optical density calculation unit 50, the measured brightness AL (λk) of each of the plurality of wavelengths λk (k = 1 to m) and the reference brightness FL (λk) obtained in advance are obtained. Multiple wavelengths of the crystalline lens 310 of the subject's eye based on the ratio to k) and the ratio of each measured size AW (λk) of the plurality of wavelengths λk to the previously obtained reference size FW (λk). The measured optical density AD _media (λk) at each of λk is calculated.

More specifically, the optical density calculation unit 50 actually measures the measured brightness AL (λk), the reference brightness FL (λk), the measured size AW (λk), and the reference size FW (λk) using the following equation (1). The optical density AD _media (λk) is calculated.

Next, in the fourth step, in the optical density estimation unit 60, the measured optical density AD _{media (λk) of each of the plurality of wavelengths λk and one or more known optical density FD media} obtained in advance for a predetermined wavelength range are used. Among (λk), _{a known optical density FD media (λk) of the type “the difference from the measured optical density AD media} (λk) is the smallest” is estimated as the estimated optical density ED _media (λ) as a predetermined condition.

More specifically, for example, one or more known optical densities FD _media (λk) obtained in advance, which are obtained based on psychological and physical methods (see, for example, J. van de Kraats et al., 2007). ). This known optical density FD _media (λk) is the coefficient of two predetermined groups: the coefficient of the first group {d _RL (age), d _TP (age), d _LY (age), d _LOUV (age), d. the _{LO (age), d neutral}} , the coefficient _{{M RL (λ)} of the second _{group, M TP (λ), M} LY (λ), M LOUV (λ), M LO (λ)}, the following It is expressed as in equation (2).

By substituting each of the wavelengths λk (k = 1 to m) into the wavelength λ of the equation (2), each known optical density FD _media (λk) of the wavelength λk is obtained. As can be seen from the equation (2), when the variable age age is changed, the same number of known optical density FD _media (λk) as the number of changed age ages is obtained. Therefore, for each of the wavelengths λk, _{the age age of the known optical density FD media} (λk) having the smallest difference from the _{measured optical density AD media} (λk) is calculated, and the age age is defined as the crystalline lens age AGE. The optical density estimation unit 60 substitutes the crystalline lens age AGE for the age age of Eq. (2) to estimate the estimated optical density ED _media (λ).

Next, in the fifth step, the optical density estimation unit 60 sets the transmittance T (λ) of the crystalline lens 310 of the eye 360 in a predetermined wavelength range based on _{the estimated optical density ED media (λ) in a predetermined wavelength range.} Calculated as the transmission spectrum of 310.

In detail, the optical density estimating unit 60, (2) age age to substitute the estimated age AGE, known optical density all constants of the coefficients of the first group _{FD media} (.lamda.k) the estimated optical density _{ED media} Let it be (λ). The estimated optical density ED _media (λ) is a function that can be obtained only at an arbitrary wavelength λ. The transmittance T (λ) is expressed by the estimated optical density ED _media (λ) as shown in Eq. (3) below.

If the predetermined wavelength range is the wavelength band of visible light as described above and is in the range of 380 nm or more and 780 nm or less, the horizontal axis has a wavelength of at least 380 nm to 780 nm, and the vertical axis is represented by equation (3). When the transmittance T (λ) is plotted, the transmission spectrum of the crystal body 310 is illustrated.

By performing each of the above steps, the transmission spectrum of the crystalline lens 310 of the subject's eye 360 is calculated for at least an arbitrary wavelength λ included in a predetermined wavelength range.

According to the estimation system 10 of the present embodiment described above, the optical density calculation unit is based on the Pulkinje image Meas [124-k] optically formed from the crystalline lens 310 of the subject's eye 360 by the image data measurement unit 20. 50, the transmittance T (λ) of the crystalline lens 310 at an arbitrary wavelength λ, that is, the transmission spectrum of the crystalline lens 310 is calculated through calculations by each of the optical density estimation unit 60 and the spectrum calculation unit 70. That is, as long as the eye 360 can be irradiated with light having a plurality of wavelengths λk and the Purkinje image Meas [124-k] can be imaged, the transmission spectrum of the crystalline lens 310 can be calculated easily and without depending on the sense of the subject.

Further, according to the estimation system 10 of the present embodiment, the known optical density FD _media (λk) is the first group corresponding to the crystalline lens age AGE and the crystalline lens age AGE of the crystalline lens 310 for each wavelength λk within the predetermined wavelength range. (Predetermined coefficient) {d _RL (AGE), d _TP (AGE), d _LY (AGE), d _LOUV (AGE), d _LO (AGE), d _neutral }. That is, if the measured brightness AL (λk) and the measured size AW (λk) are obtained from the Purkinje image Meas [124-k], the crystalline lens age AGE of the crystalline lens 310 is calculated according to the above equations (1) to (3). At the same time, the transmission spectrum of the crystalline lens 310 can be easily calculated.

Further, according to the estimation system 10 of the present embodiment, the Purkinje images Meas [124-k] and Ref [124-k] are formed by reflection on the surface 310b of the surface of the crystalline lens 310 adjacent to the vitreous 330. It is a statue. Therefore, the optical density of the crystalline lens 310 is well reflected in both the measured luminance AL (λk) and the measured size AW (λk) of the Purkinje image Meas [124-k], and the estimated optical density ED _media (λ) and the crystalline lens 310 The transmission spectrum can be calculated with high accuracy. Further, as illustrated in FIGS. 1 and 3, the angle θ4 between the optical axis of the incident light ILk and the optical axis of the reflected light RLk can be secured. This makes it easier to arrange the light source 22, the optical fiber 24, the molding filter 28, and the image pickup camera 30 of the image data measurement unit 20.

Further, according to the estimation system 10 of the present embodiment, a plurality of different wavelengths λk include 600 nm and at least one wavelength in the wavelength band of 400 nm or more and less than 600 nm. In this case, the plurality of wavelengths λk include, for example, 600 nm as a reference wavelength and a wavelength range shorter than 600 nm (that is, a range in which the optical density is high and the aging change is large). Therefore, in the wavelength range where the optical density is high, the lens age AGE of the crystalline lens 310 and the transmission spectrum of the crystalline lens 310 can be calculated more accurately than when other wavelength ranges are used. If the wavelength is about 600 nm, the change in the optical density of the crystalline lens with aging is small, and the age difference in the optical density is close to zero. Therefore, it is basically preferable to set the reference wavelength to a visible wavelength of 600 nm or more. However, the reference wavelength may be appropriately set and changed according to the conditions of the subject and the like.

Further, according to the estimation system 10 of the present embodiment, by further providing a light source 22 that irradiates the crystalline lens 310 with incident light ILk having a plurality of wavelengths λk, light sources and the like are individually prepared for the plurality of wavelengths λk. It is simple and space-saving.

Further, according to the estimation system 10 of the present embodiment, in order to form a Purkinje image Meas [124-k] having a plurality of wavelengths λk behind the crystalline lens 310 in the incident direction of the incident light ILk having a plurality of wavelengths λk. Since the gaze object 90 of the above is arranged, the movement of the crystalline lens 310 is almost stopped at the time of imaging of the Pulkinye image Meas [124-k], the Pulkinje image Meas [124-k] is stabilized, and the variation among a plurality of wavelengths λk. And errors can be suppressed.

Further, according to the transmission spectrum estimation method of the crystalline lens of the present embodiment, at least the second to fifth steps are performed using the above-mentioned estimation system 10, and the crystalline lens 310 can be easily performed without depending on the sense of the subject. The transmission spectrum of can be calculated.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments. The present invention may be modified within the scope of the gist of the invention described within the claims.

For example, in each of the above-described embodiments, the number of a plurality of wavelengths different from each other may be at least two, preferably about eight, but is not particularly limited as long as it is two or more. Further, in the above-described embodiment, as a plurality of known optical densities FD _media (λk), those represented by the equation (2) are used, but if the optical densities are represented as a function of an arbitrary wavelength (2). ) Can be used without being limited to those represented by the formula.

Further, in the above estimation system 10, a light source 22 capable of emitting light having a plurality of wavelengths λ1, ..., λm and an imaging camera capable of acquiring a Pulkinje image (image) for each wavelength λ1, ..., λm can be acquired. If there is 30, and the angle θ4 between the traveling direction of the incident light ILk emitted from the light source 22 and the imaging direction of the imaging camera 30 can be secured, the distance between the light source 22 and the imaging camera 30 and the eyes 350 and 360 is not particularly limited. The relative arrangement of the light source 22 and the imaging camera 30 with respect to the eyes 350 and 360 is not limited. For example, the light source 22 and the image pickup camera 30 may be provided in a relative arrangement that can secure an angle θ4 inside the head-mounted display, that is, inside the housing of the head-mounted display.

Further, in the estimation system 10 and the transmission spectrum estimation method of the crystalline lens described above, the acquisition time of the Purkinje image depends on the time for emitting incident light ILk having different wavelengths from the light source 22. As the rotation time (that is, switching time) of the bandpass filter in the light source 22 is shortened and the frame rate of the imaging camera 30 is shortened accordingly, the acquisition time of the Purkinje image can be shortened, and the transmission spectrum of the crystalline lens can be obtained at a higher speed. Can be estimated.

In the transmission spectrum estimation method of the crystalline lens of the above-described embodiment, the brightness and magnitude of the fourth Pulkinye image of the simulated eye at each wavelength λk were obtained as an example of the reference brightness FL (λk) and the reference size (λk). However, in the method for estimating the transmission spectrum of the crystalline lens according to the present invention, the reference luminance FL (λk) and the reference size (λk) _{need only be such that the measured optical density AD media} (λk) can be calculated, and the simulated eye. It is not limited to the brightness and size of the fourth Pulkinje image. Since the measured optical density AD _media (λk) is a physical quantity indicating how much the intensity of the light of each wavelength λk incident on the eye is attenuated before being reflected as, for example, the fourth Pulkinje image, the reference brightness FL (λk). The reference size (λk) may be any brightness and magnitude of an image formed in a predetermined wavelength band including a plurality of wavelengths λ1 to λm and whose optical density is substantially constant regardless of the wavelength, for example, a predetermined size. It may be the brightness and magnitude of an image formed by a member having a predetermined optical density in the wavelength band.

In the estimation system 10 described above, the light emitted from the light source 22 is guided by the optical fiber 24 and emitted as incident light ILk from the optical fiber 24 to the eyes 350 and 360. However, if the fourth Purkinje image 124 can be photographed, the configuration for causing the incident light ILk having a plurality of wavelengths to be incident on the eyes 350 and 360 in the estimation system 10 is not particularly limited. For example, if the light source 22 is provided with LEDs that emit light having wavelengths λ1 and ... λm, a bandpass filter or a color filter is unnecessary. Further, by using the LED as the light source 22, the intensity of the light emitted from the light source 22 can be appropriately lowered, so that it is conceivable that a cover member, a filter having holes, or the like is unnecessary. As a result, the estimation system 10 can be miniaturized.

Next, examples of the present invention will be described. The present invention is not limited to the following examples.

In this embodiment, the estimation system 10 described with reference to FIGS. 1 and 4 was prototyped. In the trial production, a commercially available xenon lamp (model number: MAX-301, manufactured by Asahi Spectral Co., Ltd.) and a plurality of color filters were used as the light source 22. In this example, in order to obtain the fourth Purkinje image 124, a total of eight wavelengths of 430 nm, 460 nm, 470 nm, 480 nm, 500 nm, 520 nm, 540 nm, and 600 nm were focused on. Eight commercially available color filters (model number: MX0430, MX0600, etc., manufactured by Asahi Spectroscopy Co., Ltd.) were used so as to correspond to the above-mentioned eight wavelengths.

As the optical fiber 24, a commercially available light guide (model number: UD0164, manufactured by Asahi Spectroscopy Co., Ltd.) was used. As shown in FIG. 6, at the exit end of the light guide, a cover member having a circular hole with a diameter of 3 mm formed in the front view was provided on the path of the incident light ILk. The cover member was formed of a black colored styrene board. High-intensity white light is emitted from the xenon lamp, but by providing a cover member at the exit end of the light guide, the intensity of the light ILk from the light source 22 can be appropriately suppressed to irradiate the eye 360. In this embodiment, k = 8 as described above.

As the imaging camera 30, a commercially available CMOS camera (model number: BFS-U3-32S4MC, FLIR Systems, Inc.) was used. A commercially available fixed focus lens (model number: TECHSPEC Series 50 mm VIS-NIR, manufactured by Edmund Optics Japan Co., Ltd.) having a focal length of 50 mm and a numerical aperture of 0.018 was provided in the light receiving portion of the CMOS camera. As the gaze object 90 shown in FIG. 4, a light bulb-colored light emitting diode (LED) (forward voltage VF = 3.2 V, forward current IF = 20 mA, luminous intensity IV = 18000 mcd) was used.

Using the prototype estimation system 10 based on the above-mentioned method for estimating the transmission spectrum of the crystalline lens, 10 subjects in the young age group (Young) from 20 to 34 years old and middle age groups from 35 to 49 years old ( The transmission spectra of the crystalline lenses of a total of 26 subjects, including 9 subjects of (Middle) and 7 subjects of the older age group (Older) from 50 to 70 years old, were estimated. FIG. 7 is an example of a first Purkinje image, a third Purkinje image, and a fourth Purkinje image formed by the eyes of a subject. In the prototype estimation system 10, as the diameter of the hole formed in the cover member becomes smaller, the first Purkinje image, the third Purkinje image, and the fourth Purkinje image are separated from each other and easily distinguished from each other, while the fourth Purkinje image is easily identified. The image becomes very small. The diameter of the hole formed in the cover member is not limited to 3 mm, but when it is set to 3 mm as an example, the first Purkinje image, the third Purkinje image, and the fourth Purkinje image can be distinguished as shown in FIG. It can be seen that the fourth Purkinje image can be sensed while being separated from each other.

The fourth Purkinje image Meas [124-k] formed by the eyes 360 of each of the 26 subjects was photographed, and the measured brightness AL (λk) and the measured brightness AL (λk) based on the information regarding the fourth Purkinje image Meas [124-k]. The measured size AW (λk) was measured. Further, the reference luminance FL (λk) and the reference size FW (λk) were measured using a commercially available simulated eye whose optical density was constant regardless of the wavelength in the visible wavelength band.

_{Next, the measured optical density AD media} (λk) was calculated for each subject based on the above-mentioned equation (1). That is, in this example, for each subject, AD _media (430 nm), AD _media (460 nm), AD _media (470 nm), AD _media (480 nm), AD _media (500 nm), AD _media (520 nm), AD _media (540 nm). ), AD _media (600 nm), eight measured optical densities were calculated. _{FIG. 8 shows the results of calculating the AD media} (λk) of each of the above eight wavelengths for the subjects of each age group (Young, Middle, Older) in the error bar format of the standard deviation. In FIG. 8, the young age group is in the negative direction, and the middle age group and the older group are in the positive direction so that the error bars of the standard deviation of _{the measured optical density AD media (λk) do not overlap with each other.} Displayed in.

Subsequently, in the optical density estimation unit 60, the wavelength λ of the above equation (2) is combined with the wavelength λk (k = 1 to 8, that is, eight wavelengths of 430 nm, 460 nm, 470 nm, 480 nm, 500 nm, 520 nm, 540 nm, and 600 nm). By substituting each of the above, a known optical density FD _media (λk) having a wavelength of λk was obtained. The age age of the known optical density FD _{media (λk), which minimizes the difference from the measured optical density AD media} (λk) at each of the above eight wavelengths of each subject, was calculated and used as the crystalline lens age AGE.

Subsequently, the optical density estimation unit 60 substituted the crystalline lens age AGE obtained for each subject into the above equation (2) to estimate the estimated optical density ED _media (λ) (λ = 430 nm to 600 nm). Since the estimated optical density ED _media (λ) is obtained by (2), the estimated optical density ED _media (λ) for each subject was obtained as a continuous function depending on the wavelength λ. FIG. 9 shows the result of calculating the average value of _{the estimated optical density ED media} (λ) of each age group in order to see the tendency of the change of the transmission spectrum of the crystalline lens for each age group.

Subsequently, the calculated average estimated optical density ED _media (λ) of each age group is substituted into the above equation (3), and the transmittance T (λ) of the crystal bodies of a plurality of subjects in each age group (hereinafter, The average transmittance _TAVE (λ)) was calculated. _{FIG. 10 shows the results of calculating the average transmittance TAVE} (λ) in the visible wavelength band of 380 nm or more and 700 nm or less in each age group, that is, the average transmittance spectrum of the crystalline body in the visible wavelength band of a plurality of subjects in each age group. Is shown.

As described above, in this embodiment, based on the above-mentioned method for estimating the transmission spectrum of the crystalline lens, the fourth Pulkinje image of the crystalline lens of each subject of a total of 26 subjects in the three age groups is acquired to obtain the fourth Pulkinje image of the three age groups. The average transmission spectrum of the crystalline lens of was calculated. From the three transmission spectra shown in FIG. 10, the tendency of changes in the transmission spectrum of the crystalline lens depending on the age group can be read.

For example, as shown in FIG. 10, in the entire wavelength band from 400 nm to 700 nm, the average transmittance _TAVE (λ) of the crystalline body is lower in the middle age group (Middle) than in the young age group (Young), and further. _{The average transmittance TAVE} (λ) of the crystalline body was lower in the older group (Older) than in the middle age group (Middle). From this, it was shown that the optical density of the crystalline lens increases with aging, as is already known. However, in the present embodiment, as shown in FIG. 10, young average difference in transmittance T _{AVE (lambda)} between the ages and the middle ages, and the average transmittance T _AVE of the middle age and older layer ( The difference of λ) could be quantitatively obtained as a transmission spectrum over the visible wavelength band of 380 nm or more and 700 nm or less. _{From this, it was found that the difference in the average transmittance TAVE} (λ) of the crystalline body between the young age group and the middle age group is not constant in the visible wavelength band of 380 nm or more and 700 nm or less, and similarly, the young age group and the middle age group. _{It was found that the difference in the average transmittance TAVE} (λ) of the crystal body from the layer is not constant in the visible wavelength band of 380 nm or more and 700 nm or less. Further, in the same wavelength lambda, young age and the middle age and the average transmittance T _AVE of the lens of the middle age and advanced age in comparison with the difference between the average transmittance of the lens T _{AVE (λ) (λ)} the difference in the difference is large, and young age and middle age and average transmittance T _AVE of the lens of the difference and the middle ages and advanced age of the average transmittance T _AVE of the lens _(lambda) of _(lambda) It was found that the difference from the above is not constant in the visible wavelength band of 380 nm or more and 700 nm or less. _{In particular, in the visible wavelength band of 450 nm or more and 500 nm or less, the difference in the average transmittance TAVE} (λ) of the crystalline lens between the middle-aged group and the elderly group was larger than that of other visible wavelength bands. From this, it was found that the optical density of the crystalline lens of the elderly group tends to be higher with respect to blue visible light than with red or green visible light.

As described above, from the results of this example, according to the transmission spectrum estimation method of the crystal body described above, after photographing a plurality of fourth Pulkinje images having a predetermined wavelength, the optical density of the crystal body having a predetermined wavelength is simply determined. It was confirmed that the transmission spectrum of the crystalline body in the visible wavelength band including a predetermined wavelength can be calculated as well as the acquisition. By obtaining the transmission spectrum in the visible wavelength band, the visual and non-visual functions of the subject reflected in the change in the transmission spectrum of the crystalline lens of each age group can be grasped, and the diagnosis, living environment and use suitable for the subject can be understood. Can make proposals for assistive devices, etc.

In this example, in order to examine the trend of changes in the transmission spectrum of the crystalline lens for each age group, _{the average of the estimated optical densities ED media} (λ) at each of the eight wavelengths of a plurality of subjects in each age group. The value was calculated. However, for example, if you want to know the change in the transmission spectrum of the crystalline lens for each subject even within the same age group, formula (3) is based on _{the estimated optical density ED media (λ) estimated for each of the eight wavelengths for each subject.} The transmittance T (λ) for each subject may be calculated from. By doing so, the transmission spectrum of the crystalline lens of each subject can be calculated, and the relationship between the change in the transmission spectrum of the crystalline lens of each subject with age and the factors of the change and lifestyle and the like can be investigated.

10 Estimation system (lens transmission spectrum estimation system)
20 Image data measurement unit 50 Optical density calculation unit 60 Optical density estimation unit 70 Spectrum calculation unit

Claims (7)

Image data in which the brightness of a plurality of images having different wavelengths formed by the crystalline lens is measured as the measured brightness for each of the plurality of different wavelengths, and the size of the image is measured as the measured size for each of the plurality of different wavelengths. Actual measurement part and
The ratio of the measured brightness of each of the plurality of different wavelengths to the reference brightness obtained in advance for each of the plurality of different wavelengths, the measured size of each of the plurality of different wavelengths, and the plurality of each other. An optical density calculation unit that calculates the measured optical density at each of the plurality of different wavelengths of the crystalline lens based on the ratio to the reference size obtained in advance for each of the different wavelengths.
An optical density that satisfies a predetermined condition for the measured optical density at each of the plurality of different wavelengths and is estimated as an estimated optical density by using a known optical density obtained in advance for a predetermined wavelength range including the plurality of different wavelengths. Estimator and
A spectrum calculation unit that calculates the transmittance of the crystalline lens in the predetermined wavelength range as the transmission spectrum of the crystalline lens based on the estimated optical density in the predetermined wavelength range.
A transmission spectrum estimation system for the crystalline lens. The known optical density obtained in advance for the predetermined wavelength range is calculated based on the crystalline lens age of the crystalline lens for each wavelength within the predetermined wavelength range and a predetermined coefficient according to the crystalline lens age.
The transmission spectrum estimation system for a crystalline lens according to claim 1. The image is an image formed by reflection on the surface of the crystalline lens adjacent to the vitreous body.
The transmission spectrum estimation system for a crystalline lens according to claim 1 or 2. The plurality of different wavelengths include 600 nm and at least one wavelength within the wavelength band of 400 nm or more and less than 600 nm.
The transmission spectrum estimation system for a crystalline lens according to any one of claims 1 to 3. The crystalline lens is further provided with a light source for irradiating the plurality of light having different wavelengths.
The transmission spectrum estimation system for a crystalline lens according to any one of claims 1 to 4. A gaze object is arranged behind the crystalline lens in the direction of incidence of the plurality of light having different wavelengths on the crystalline lens.
The transmission spectrum estimation system for a crystalline lens according to any one of claims 1 to 5. The brightness of a plurality of images having different wavelengths formed by the crystalline lens is measured as the measured brightness for each of the plurality of different wavelengths, and the size of the image is measured as the measured size for each of the plurality of different wavelengths.
The ratio of the measured luminance of each of the plurality of different wavelengths to the reference luminance obtained in advance for each of the plurality of different wavelengths, the measured size of each of the plurality of different wavelengths, and the plurality of each other. Based on the ratio to the reference size obtained in advance for each of the different wavelengths, the measured optical density at each of the plurality of different wavelengths of the crystal body was calculated.
Of the measured optical densities at each of the plurality of different wavelengths and the known optical densities obtained in advance for a predetermined wavelength range including the plurality of different wavelengths, the predetermined optical densities including the plurality of different wavelengths are obtained in advance. The known optical density having the smallest difference from the known optical density is estimated as the estimated optical density, and the difference is estimated.
Based on the estimated optical density in the predetermined wavelength range, the transmittance of the crystalline lens in the predetermined wavelength range is calculated as the transmission spectrum of the crystalline lens.
A method for estimating the transmission spectrum of the crystalline lens, including the above.

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