JP2002000570A - Positioning device for measuring eyeball - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device useful for practically measuring a glucose concentration of aqueous homor and by which measurement can always be made in the same length of an optical path by using eyeballs which can solve such a problem that, in a method of measuring a glucose concentration of aqueous homor based on absorbing quantity of a light passing through eyeballs or the rotary angle of a polarization surface to estimate a glucose concentration in blood, since the measurements are determined based on the glucose concentration and the lengths of optical paths and a measurement must be made at a position where the same length of an optical path is always given, a slight deviation of the position to be lightened causes a large variation in the length of the optical path because the eyeballs are globular. SOLUTION: The device is provided with a light projector 1, a reflector 3 and a multi-channel light receiver 4. To make the device practical, there is also provided an electronic circuit for detecting and displaying a light receiver receiving lights and, preferably, a slight moving device.

Description

Translated fromJapanese

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【産業上の利用分野】眼球に光を通してその吸収量又は
偏光面の回転角から眼房水のグルコース濃度を測定し、
血中のグルコース濃度を推定する方法がある。測定値は
グルコース濃度と光路長により決定され、正確な測定を
行うためには常に同じ光路長を与える場所で測定を行う
必要があるが、眼球は球状であり光を当てる場所が僅か
でもずれるとその光路長は大きく変化してしまう。本発
明は眼球を利用したグルコース濃度測定の実用化のため
に有用な、常に同じ光路長で測定が出来る方法及び装置
を提供する。BACKGROUND OF THE INVENTION Glucose concentration in aqueous humor is measured from the amount of light absorbed or the rotation angle of the plane of polarization by passing light through the eyeball.
There is a method for estimating the blood glucose concentration. The measurement value is determined by the glucose concentration and the optical path length, and it is necessary to always perform the measurement at a place that gives the same optical path length in order to perform an accurate measurement, but if the eyeball is spherical and the place where the light is applied is slightly shifted, The optical path length changes greatly. The present invention provides a method and an apparatus useful for practical use of glucose concentration measurement using an eyeball, which can always perform measurement with the same optical path length.

【０００２】[0002]

【従来の技術】眼球を利用したグルコース測定は新しい
技術であり、眼球の同じ場所に光を通すための標準的な
方法はまだない。例えば眼鏡のように測定器を耳と鼻で
支持して測定する方法、測定器を顔面に押しつけて支持
して測定する方法等が提案されているが、いずれも確立
された方法とは言い難い。2. Description of the Related Art Eye-based glucose measurement is a new technique, and there is no standard method for transmitting light to the same part of the eye. For example, a method of measuring by supporting the measuring device with ears and nose like eyeglasses, a method of measuring by pressing the measuring device against the face, and the like have been proposed, but none of them are established methods. .

【０００３】[0003]

【発明が解決しようとする課題】眼球に光を通してグル
コース濃度を測定する場合、約１０ミリメートルの光路
長が必要と言われている。眼球の直径は約２５ミリメー
トルと言われており、その周辺の弦の長さ１０ミリメー
トルを確保するには光は角膜先端から約２ミリメートル
のあたりを通る。この辺では、光は角膜に斜めに入射す
る為、角膜先端からの距離が少し変化しても光路長は大
きく変化する。概算では０．１ミリメートル変化すると
光路長は約３％程度変わってしまう。測定の再現性とし
て５％が要求されており、これを満足させるには毎回の
測定に於いて、光路長の変動をこれ以下に納めなくては
ならず、何らかの位置決めの方法が必要となる。When measuring the glucose concentration by passing light through the eyeball, it is said that an optical path length of about 10 millimeters is required. The diameter of the eyeball is said to be about 25 millimeters, and light passes around 2 millimeters from the tip of the cornea to secure a chord length of 10 millimeters around the eyeball. In this side, since the light enters the cornea obliquely, the optical path length greatly changes even if the distance from the corneal tip slightly changes. Approximately, a change of 0.1 mm will change the optical path length by about 3%. The reproducibility of the measurement is required to be 5%, and in order to satisfy this, the fluctuation of the optical path length must be kept below this in every measurement, and some positioning method is required.

【０００４】[0004]

【課題を解決するための手段】人間の目はかなり良く光
を反射する。発明者は、この反射光を利用して光を通す
位置を決める事を考えた。図１に示すごとく、角膜に斜
めに照射した光は、角膜表面で反射光と入射光とに分か
れる。入射光は角膜を円で近似した場合の弦に沿ってそ
のまま直進し、反対側の角膜に達し、眼球の外に出る。
反射光は空気中を直進し失われるが、ここに平面鏡を置
き、光を入射光が角膜から出てくる場所に戻してやれ
ば、ここで再び反射して入射光と合体し、受光器に導か
れる。SUMMARY OF THE INVENTION The human eye reflects light fairly well. The inventor has considered using this reflected light to determine a position through which light passes. As shown in FIG. 1, light obliquely applied to the cornea is split into reflected light and incident light on the surface of the cornea. The incident light travels straight along the chord when the cornea is approximated by a circle, reaches the opposite cornea, and exits the eyeball.
The reflected light goes straight through the air and is lost.However, if a plane mirror is placed here and the light is returned to the place where the incident light comes out of the cornea, it is reflected again and united with the incident light and guided to the light receiver. I will

【０００５】この光学系、即ち投光器、鏡、受光器を一
体としてその位置をずらせてみると、照射光が角膜に当
たる位置が変化するため、鏡での反射光は入射光の角膜
からの出口には戻されず受光器からはずれてしまう。即
ち、反射光が受光器に入るような位置関係に置いたとき
のみ角膜と本光学系の位置関係が測定に適した状態とな
る。When the position of this optical system, ie, the projector, the mirror, and the light receiver, is shifted, the position at which the irradiation light strikes the cornea changes. Therefore, the reflected light from the mirror reflects the incident light at the exit from the cornea. Is not returned and comes off the light receiver. That is, the positional relationship between the cornea and the present optical system is in a state suitable for measurement only when the positional relationship is such that the reflected light enters the light receiver.

【０００６】[0006]

【発明の実施の形態】本発明の内容を模式的に説明す
る。光は界面に於いて常に入射光と反射光に分離する。
反射光は界面に立てた垂線と入射光がなす角度で反射さ
れ、入射光は屈折の法則に従ってその進行方向を変える
が、発明の内容を説明するためにはこの屈折は無視して
も誤解を招くことはない。説明が煩雑になるのを防ぐた
め直進するとして図示する。角膜は円弧で示す。DESCRIPTION OF THE PREFERRED EMBODIMENTS The contents of the present invention will be schematically described. Light always separates at the interface into incident light and reflected light.
Reflected light is reflected at the angle between the perpendicular to the interface and the incident light, and the incident light changes its direction of travel according to the law of refraction. I will not invite you. In order to prevent the description from becoming complicated, it is illustrated as going straight. The cornea is indicated by an arc.

【０００７】図１に測定に必要な１０ミリメートルの光
路長を確保した場合を一例として示す。光は水平方向に
角膜に入射するものとし、光軸に沿った水平断面図を示
す。投光器１から出た光５は角膜２に当たり、入射光６
と反射光７に分かれる。入射光６は角膜の内側の眼房水
中を進行し、再び角膜２の外に出て受光器４に入る。反
射光７は鏡３で反射し、再度角膜２の表面で反射し受光
器４にはいる。ここに投光器１，鏡３及び受光器４は一
体化された光学系を形成するためこれを測定光学系８と
呼ぶ。FIG. 1 shows, as an example, a case where an optical path length of 10 mm required for measurement is secured. Light is assumed to be incident on the cornea in the horizontal direction, and a horizontal sectional view along the optical axis is shown. The light 5 emitted from the projector 1 hits the cornea 2 and the incident light 6
And reflected light 7. The incident light 6 travels through the aqueous humor inside the cornea, exits the cornea 2 again, and enters the light receiver 4. The reflected light 7 is reflected by the mirror 3 and again reflected on the surface of the cornea 2 and enters the light receiver 4. Here, the light projector 1, the mirror 3 and the light receiver 4 form an integrated optical system, which is called a measuring optical system 8.

【０００８】図２には測定光学系８が角膜に遠すぎた時
を示す。この時も投光器１から出た光５は角膜２で入射
光６と反射光７に分かれ、入射光６は直進して受光器４
に入るが、反射光７は鏡３で反射しても角膜２に投射せ
ず、受光器４には入らない。この時は図から明らかなよ
うに光路長は不足し、グルコース濃度は小さく測定され
る。このまま測定光学系８を角膜２に近づけてゆけば反
射光７の光路は角膜２に近づいてゆき、角膜２に投射す
るようには成るがその反射光７はまだ受光器４には入ら
ない。さらに近づいてゆき、図１の状態になった所で反
射光７は受光器４に入り、１０ミリメートルの光路長が
確保される。FIG. 2 shows when the measuring optical system 8 is too far from the cornea. Also at this time, the light 5 emitted from the light projector 1 is divided into incident light 6 and reflected light 7 by the cornea 2, and the incident light 6 goes straight to the light receiver 4
Although the reflected light 7 is reflected by the mirror 3, it does not project on the cornea 2 and does not enter the light receiver 4. At this time, as is clear from the figure, the optical path length is insufficient, and the glucose concentration is measured small. If the measurement optical system 8 is moved closer to the cornea 2 as it is, the optical path of the reflected light 7 approaches the cornea 2 and projects on the cornea 2, but the reflected light 7 has not yet entered the light receiver 4. Further, the reflected light 7 enters the light receiver 4 when the state shown in FIG. 1 is reached, and an optical path length of 10 mm is secured.

【０００９】図３には測定光学系８が角膜に近すぎた時
を示す。この時も投光器１から出た光５は角膜２で入射
光６と反射光７に分かれ、入射光６は直進して受光器４
に入るが、反射光７は鏡３で反射して角膜２に投射する
が再度反射され、受光器４には入らない。この時は図か
ら明らかなように光路長は過大となり、グルコース濃度
は大きく測定される。このまま測定光学系８を角膜２か
ら遠ざけてゆけば反射光７の光路は図３上で反時計方向
に回転し、やがては反射光７が受光器に入る、即ち図１
の状態になって１０ミリメートルの光路長が確保され
る。FIG. 3 shows when the measuring optical system 8 is too close to the cornea. Also at this time, the light 5 emitted from the light projector 1 is divided into incident light 6 and reflected light 7 by the cornea 2, and the incident light 6 goes straight to the light receiver 4
The reflected light 7 is reflected by the mirror 3 and projected on the cornea 2 but is reflected again and does not enter the light receiver 4. At this time, as is clear from the figure, the optical path length becomes excessive, and the glucose concentration is measured to be large. If the measuring optical system 8 is kept away from the cornea 2 as it is, the optical path of the reflected light 7 rotates counterclockwise in FIG. 3, and the reflected light 7 enters the photodetector soon.
And an optical path length of 10 mm is secured.

【００１０】以上の説明から分かるように、受光器４と
して紙面の上下方向に多チャンネルの物を使用すること
が本装置を使いやすくするために有効である。図４は図
２と同じ状態を示す図であるが光検出器として図２の受
光器４の上に近副受光器４１，下に遠副受光器４２が追
加されている。図４の状態ですでに反射光７が遠副受光
器４２に入っている、即ち測定光学系８が正しい位置か
ら現在遠くにあることが分かり、使用者は測定光学系８
を更に角膜に近づければ正しい測定が出来ることがわか
る。逆に近副受光器４１が反射光７を検出した場合は、
使用者は測定光学系８を角膜から離せばよい。As can be seen from the above description, it is effective to use a multi-channel object as the light receiver 4 in the vertical direction on the paper surface in order to make the present apparatus easy to use. FIG. 4 is a view showing the same state as FIG. 2, except that a near sub-light receiver 41 is added above the light receiver 4 of FIG. In the state shown in FIG. 4, it is known that the reflected light 7 has already entered the remote auxiliary light receiver 42, that is, the measuring optical system 8 is presently far from the correct position.
It can be understood that correct measurement can be performed by bringing the sample closer to the cornea. On the other hand, when the near auxiliary light receiver 41 detects the reflected light 7,
The user only needs to separate the measuring optical system 8 from the cornea.

【００１１】以上の図１から図４は角膜２を近似した球
面の中心９を含む水平断面について測定が行われるもの
として説明した。測定光学系８がこの水平断面上にある
保証はない。使用者が測定器を紙面より上又は下に保持
して測定を行おうとする場合には光路長の保証はない。
この場合は近似球面の中心９を含まない水平断面で測定
を行うこととなり、直径の小さな円の弦に沿って測定が
行われることとなり、望ましくない。この誤差に対して
は、受光器４の上に上副受光器４３，下に下副受光器４
４を設けることが有効である。球の中心９を含まない断
面に入射した光は球の中心９と光軸とを含む面内で反射
するので、測定光学系８が紙面より上に有れば反射光７
は上副受光器４３に入射し、下に有れば下副受光器４４
に入る。この受光器の信号を監視することにより測定光
学系８が正規の場所よりも上にあるのか下にあるのかが
判定でき、その高さが修正される。図５に多チャンネル
受光器の例をしめす。FIGS. 1 to 4 have been described on the assumption that the measurement is performed on a horizontal cross section including the center 9 of the spherical surface approximating the cornea 2. There is no guarantee that the measuring optics 8 is on this horizontal section. There is no guarantee of the optical path length when the user attempts to perform measurement while holding the measuring device above or below the page.
In this case, the measurement is performed on a horizontal section not including the center 9 of the approximate spherical surface, and the measurement is performed along the chord of a circle having a small diameter, which is not desirable. For this error, the upper sub-light receiver 43 is placed above the light receiver 4 and the lower sub-light receiver 4 is placed below.
4 is effective. Light incident on a cross section that does not include the center 9 of the sphere is reflected within a plane that includes the center 9 of the sphere and the optical axis, so that if the measurement optical system 8 is above the plane of the paper, the reflected light 7
Is incident on the upper auxiliary light receiver 43, and if it is below, the lower auxiliary light receiver 44
to go into. By monitoring the signal of the light receiver, it can be determined whether the measuring optical system 8 is above or below a regular place, and its height is corrected. FIG. 5 shows an example of a multi-channel light receiver.

【００１２】以上は本発明の光学系について説明した
が、実用に当たっては、どの受光器に光が入ったかを検
出し測定光学系８をどの方向に移動すればよいかを示す
電子回路及び、望ましくは位置調整のための微量移動装
置を付加することが有用である。Although the optical system of the present invention has been described above, in practical use, an electronic circuit which detects which light receiver has entered light and indicates in which direction the measuring optical system 8 should be moved, and preferably It is useful to add a micro-moving device for position adjustment.

【００１３】[0013]

【発明の効果】眼球に光を通してその吸収量又は偏光面
の回転角から眼房水のグルコース濃度を測定し、血中の
グルコース濃度を推定する方法がある。測定値はグルコ
ース濃度と光路長により決定され、正確な測定を行うた
めには常に同じ光路長を与える場所で測定を行う必要が
あるが、眼球は球状であり光を当てる場所が僅かでもず
れるとその光路長は大きく変化してしまう。本発明は眼
球を利用したグルコース濃度測定の実用化のために有用
な、常に同じ光路長で測定が出来る方法及び装置を提供
する。There is a method of estimating the glucose concentration in blood by measuring the glucose concentration of aqueous humor from the amount of light absorbed or the rotation angle of the plane of polarization by passing light through the eyeball. The measurement value is determined by the glucose concentration and the optical path length, and it is necessary to always perform the measurement at a place that gives the same optical path length in order to perform an accurate measurement, but if the eyeball is spherical and the place where the light is applied is slightly shifted, The optical path length changes greatly. The present invention provides a method and an apparatus useful for practical use of glucose concentration measurement using an eyeball, which can always perform measurement with the same optical path length.

【図面の簡単な説明】[Brief description of the drawings]

【図１】本発明による眼球測定位置決め用具が正常に装
着された状態を示す。FIG. 1 shows a state in which an eyeball measurement and positioning tool according to the present invention is normally worn.

【図２】本発明による眼球測定位置決め用具が角膜より
遠方に装着された状態を示す。FIG. 2 shows a state in which the eyeball measuring and positioning tool according to the present invention is mounted farther than the cornea.

【図３】本発明による眼球測定位置決め用具が角膜に近
すぎる状態を示す。FIG. 3 shows a situation in which the eye-measuring positioning device according to the invention is too close to the cornea.

【図４】光検出器として３チャンネル受光器を使用する
事により、装着位置が遠近どちらにずれているかの表示
を出すことが出来ることを示す。FIG. 4 shows that by using a three-channel light receiver as a photodetector, an indication can be given as to whether the mounting position is far or near.

【図５】利用される多チャンネル受光器の一例を示す。FIG. 5 shows an example of a multi-channel light receiver used.

【符号の説明】[Explanation of symbols]

１ 投光器 ２ 角膜 ３ 鏡 ４ 受光器 ５ 投射光 ６ 入射光 ７ 反射光 ８ 測定光学系 ９ 角膜近似球の中心 ４１ 近副受光器 ４２ 遠副受光器 ４３ 上副受光器 ４４ 下副受光器 DESCRIPTION OF SYMBOLS 1 Projector 2 Cornea 3 Mirror 4 Receiver 5 Projection light 6 Incident light 7 Reflected light 8 Measurement optical system 9 Center of approximate corneal sphere 41 Near auxiliary light receiver 42 Far auxiliary light receiver 43 Upper auxiliary light receiver 44 Lower auxiliary light receiver

Claims (2)

Translated fromJapanese

【特許請求の範囲】[Claims]【請求項１】レーザー光を投光する手段と、投光部と同
軸上に配置された受光部と、この光軸と所定の距離離れ
て光軸に平行に配置された鏡とからなり、この鏡がその
ほぼ中央に立てた垂線が投光部と受光部を結ぶ直線とそ
のほぼ中央で交わる向きに配置される事を特徴とする、
眼球の所定の部分に光を通す為に使用される眼球測定位
置決め用具。1. A device for projecting a laser beam, comprising: a light receiving unit disposed coaxially with a light projecting unit; and a mirror disposed at a predetermined distance from the optical axis and parallel to the optical axis; The mirror is arranged so that a vertical line set at substantially the center thereof intersects a straight line connecting the light emitting part and the light receiving part at substantially the center thereof.
An eyeball measurement and positioning tool used to pass light through a predetermined portion of the eyeball.【請求項２】請求項１に於いて、その受光部が多チャン
ネルの光検出器から成ることを特徴とする眼球測定位置
決め用具。2. An eyeball measuring and positioning tool according to claim 1, wherein said light receiving portion comprises a multi-channel photodetector.