JPH0394728A - Ophthalmic apparatus - Google Patents

Abstract

PURPOSE:To perform measurement corresponding to a purpose by stopping a measuring means at an arbitrary position by enabling the stopping position of the measuring means to be set arbitrarily at a position brought in contact with a cornea or in the periphery of it. CONSTITUTION:An ultrasonic probe 12 driven in the direction of the eye E to be inspected with a motor 16 and a wire 17 stops the driving of the motor 16 to an eye E side when a probe holder 13 is brought into contact with either a microswitch 20a, 20b, or 20c selected with a selection switch 21. For example, when the microswitch 20a is selected, the probe 12 is stopped at a position before it is brought in contact with the eye E. Also, when the microswitch 20b is selected, the probe 12 is stopped at a state where it is almost brought in contact with the eye E, and when the microswitch 20c is selected, the probe 12 extrudes the eye E further forward than a position mounted and being brought into contact and is stopped at a state where contact pressure is applied on the eye E.

Description

【発明の詳細な説明】 ［産業上の利用分野］ 本発明は，被検眼情報を得るために被検眼に接触させる
測定系を有する眼科器械に関するものである． ［従来の技術］ 例えば、白濁した水晶体を摘出し、人工水晶体を挿入す
る白内障手術において、適正な人工水晶体を選定する場
合に、角膜屈折力の測定は光学式測定装置で行い、次に
角膜から網膜までの長さつまり眼軸長を超音波式眼軸長
測定装置で求め、両者から得られたデータを基に所定の
計算式によって水晶体の屈折力を算出している．このた
めに角膜屈折力及び眼軸長測定のための複合化された装
置も提案されている． このような装置で測定を行う場合に、先ず装置の顔受け
部に患者の顔を固定し摺動台によるアライメントを行っ
て、被検眼と装置との距離を最適距離とし，ここで非接
触式に角膜屈折力を求める．次に、押釦等の指令により
超音波探触子を被検眼側に電動機等により駆動させて、
被検眼の角膜に接触させ眼軸長を求めている． ［発明が解決しようとする課題１ しかし、超音波による眼軸長の測定においては、例えば
被検眼の白内障が進み視力が殆ど無い場合や、検者が十
分に熟練している場合には正確な眼軸長の測定が容易で
ある．しかし、検者が不慣れな場合や被検眼が十分な視
力を有している場合には、探触子の接近によって被検眼
が動いてしまい正確な眼軸長の測定ができないことがあ
る．そこで、被検者の状態や検者の好み或いは検者の熟
練度により、超音波探触子の駆動方法に選択の余地を持
たせたいという要望がある． 本発明の目的は，上述の問題点を解消し、測定系や摺動
台の駆動方向について各位置で駆動を停止制限する検出
手段を有し、測定手段を選択或いは移動変更できるよう
な機能を有する眼科器械を提供することである． ［課題を解決するための手段］ 上記の目的を達或するために、本発明に係る眼科器械に
おいては，被検眼の角膜に接触して被検眼情報を検出す
る測定手段と、該測定手段を被検眼方向に駆動させる駆
動手段と、前記測定手段を所定位置で駆動停止させるた
めの検知手段と、前記測定手段の角膜への接触圧をほぼ
一定とする調整手段とを備えた眼科器械において、前記
測定手段の停止位置を角膜に接触する位置及びその前後
に可変に設定可能としたことを特徴とするものである． ［作用］ 上記の構戒を有する眼科器械は，被検眼の角膜に接触す
る測定手段任意の位置で停止して目的に応じた測定を行
う． ［実施例］ 本発明を図示の実施例に基づいて詳細に説明する． 第１図において、摺動台ｌ上に設けられた木体２を被検
眼Ｅに対し所定位置に設定した後に角膜屈折力を測定す
る第１の測定系と、この位置から被検眼Ｅ方向に移動さ
せ、角膜に接触させて計測する超音波探触子を含み、眼
軸長を求めるための第２の測定系が設けられている．第
１の測定系においては、被検眼Ｅに対向して対物レンズ
３が配置され、その後方に光路に沿ってミラー４、５，
結像レンズ６、撮像素子７が配置され、この撮像素子７
の出力はテレビモニタ８に接続されている．そして、対
物レンズ３、ミラー４、５は一体構造とされ、電動機９
により駆動するワイヤ１０により上下動し得るようにな
っている．また対物レンズ３の周囲には、第２図に示す
ように発光ダイオードから或る例えば４個の光源１１ａ
〜ｌｉｄが配置されている．更に、第２の測定系におい
ては、ミラー４の後方に配置された超音波探触子ｌ２が
探触子ホルダｌ３を介して摺動案内部材１４により保持
され、この超音波探触子ｌ２はばねｌ５によって超音波
探触子１２の被検眼Ｅの角膜への接触圧をほぼ一定にす
る調整手段とされている．また、探触子ホルダ１３は電
動機１６により動くワイヤ１７によって前後進し得るよ
うになっている． ここで、光源１１ａ−ｌｉｄからの光束を所定の空間距
離を隔てて被検眼Ｅの角膜に投影すると，角膜の凸面鏡
作用によって光源ＩＬａ〜ｌｉｄの角膜反射像が形威さ
れるわけであるが、角膜の曲率半径や乱視度の大きさに
応じてこれらの角膜反射像の光点位置の相ＴＬ関係が変
化するために、この変化を検出することによって、角膜
屈折力や角膜乱視度、軸角度を求めることができること
は周知の通りである． このための第１の測定系は、前述したように光源１１ａ
−ｌｉｄによる角膜反射像を対物レンズ３、ミラー４、
５、結像レンズ６から或る光学系により撮像素子７に結
像させることによって検知している．この検知信号を図
示しない電気回路において信号処理を行い，更には演算
処理等を行って角膜屈折力、角膜乱視度、軸角度を求め
る．なお、撮像素子７は測定信号検出のみでなく、被検
眼Ｅに対して摺動台１上の木体２を前眼部像の結像状態
等から判断して、適正な所定位置に設定するための位置
確認手段としての機能も持っている． 第２の測定系は前述したように、超音波探触子１２．探
触子ホルダ１３、摺動案内部材ｌ４、ばね１５により構
威されている．探触子１２の中には超音波発振子、受信
子が内蔵されており、ケーブルを介して図示しない電気
回路部と接続されている．超音波探触子１２を被検眼Ｅ
の角膜に接触させた状態で、探触子１２の先端から超音
波パルスを発振し、被検眼Ｅの角膜からの反射エコーを
受信することによって被検眼Ｅの網膜までの眼軸長を検
出することができる．このようにして、被検眼Ｅの角膜
屈折力と眼軸長を測定すると、これらの値から経験的に
得られた計算式により水晶体の屈折力を算出することが
できる． 本実施例では、角膜屈折力測定時には超音波探触子ｌ２
は角膜屈折力測定の光路を妨げないようにミラー４の後
方に退避されているが、図示しない切換スイッチを眼軸
長測定モードに切換えると、対物レンズ３、ミラー４、
５が電動機９、ワイヤｌＯによって駆動されて下降し、
次いで探触子１２が電動機ｌ６、ワイヤ１７により探触
子ホルダ１３，ばねｌ５を介して被検眼Ｅの方向に駆動
される． このときの超音波探触子ｌ２の駆動方法については、検
者が測定に十分熟練している場合や、被検眼Ｅに殆ど視
力の無い場合には、電動機１６、ワイヤ１７により角膜
に探触子ｌ２を駆動させて直接接触して眼軸長を測定す
る． また、検者の測定技術が未熟な場合や、被検眼Ｅが十分
な視力を保持している場合には，探触子１２を後述する
手段により被検眼Ｅの稍々手前まで駆動させて停止する
．その後に、被検眼Ｅの前方視を保持させたまま、摺動
台１上の操作桿１ａにより木体２を静かに被検眼Ｅ側に
摺動させて接触子ｌ２を角膜に接触させて眼軸長を測定
する．なお、被検眼Ｅの角膜に探触子１２を接触のみに
留めて駆動を停止させ、次に木体２を検者が摺動して測
定する場合もある． 第３図、第４図は被検眼Ｅに対する超音波探触子ｌ２の
停止位置を可変とする実施例を示し、探触子ホルダ１３
の移動に伴って別個に接触する３個ノマイクロスイッチ
２０ａ、２０ｂ、２０ｃが設けられている．そして、こ
れらのスイッチ２０ａ、２０ｂ、２０ｃには電動機１６
が接続され、それぞれのスイッチ２０ａ．２０ｂ、２０
ｃの回路は、選択スイッチ２１によって電源と導通する
ようになっている． 前述のように、電動機１６、ワイヤ１７により被検眼Ｅ
の方向に駆動される超音波探触子ｌ２は、探触子ホルダ
１３が選択スイッチ２１により選択されたマイクロスイ
ッチ２０ａ、２０ｂ，２０ｃの何れかに当接した時に電
動機ｌ６の被検眼Ｅ側への駆動を停止する．例えば、マ
イクロスイッチ２０ａを選択した場合には、接触子１２
は被検眼Ｅに接触する手前で停＋ｈする．また，マイク
ロスイッチ２０ｂを選択した場合には、接触子１２が被
検眼Ｅにほぼ接触した状態で停止するようにし、マイク
ロスイッチ２０ｃを選択した場合には、接触子１２は被
検眼Ｅと接触した位置よりも更に前に押し出て、被検眼
Ｅに接触圧を掛けるような状態で停止する．ただし、前
述のようにばね１５により接触圧を一定圧にすることが
でき、測定値に殆ど影響を与えないようにされている． このように、被検眼Ｅに対する超音波探触子１２の停止
位置を可変とする第３図、第４図に示す実施例では、３
個のマイクロスイッチ２０ａ，２０ｂ、２０ｃを設置し
て、選択スイッチ２ｌより切換えて機能させているが、
１個のマイクロスイッチを案内部材等によりその位置を
可変して同様の接触をさせるとすることもできる．また
，マイクロスイッチ２０に代えてフォトセンサや磁気セ
ンサ等を用いれば、接触子ホルダ１３を非接触で制御で
き，超音波探触子ｌ２の動きを滑らかにすることができ
る．また、電動機１６をステッピング電動機にして、電
動機１６に与える駆動パルス数を設定可変としても同様
な目的を達戊することが可能である． ［発明の効果］ 以上説明したように本発明に係る眼科器械は、被検眼に
対し超音波探触子の電動駆動停Ｉヒ位置を、マイクロス
イー２チ等の制御や電動機の駆動パルスの変更等により
可変とすることで、被検者や検者の都合に応じて適当な
位置を選択することができ、眼軸長の測定の精度が向上
し測定時間も短縮できる利点がある．DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an ophthalmological instrument having a measurement system that is brought into contact with the eye to be examined in order to obtain information about the eye to be examined. [Prior Art] For example, in cataract surgery where a cloudy crystalline lens is removed and an artificial lens is inserted, when selecting an appropriate artificial lens, the corneal refractive power is measured using an optical measuring device, and then the corneal refractive power is measured using an optical measuring device. The length to the retina, that is, the axial length of the eye, is determined using an ultrasonic axial length measuring device, and the refractive power of the crystalline lens is calculated using a predetermined formula based on the data obtained from both. For this purpose, a combined device for measuring corneal refractive power and axial length has also been proposed. When performing measurements with such a device, first fix the patient's face on the face holder of the device, perform alignment using a sliding table, set the optimal distance between the eye to be examined and the device, and then use the non-contact method. Find the corneal refractive power. Next, the ultrasonic probe is driven toward the eye to be examined by an electric motor or the like in response to a command from a push button or the like.
The axial length is determined by contacting the cornea of the eye being examined. [Problem to be Solved by the Invention 1] However, in measuring the axial length using ultrasonic waves, it is difficult to obtain accurate measurements when, for example, the subject's eye has developed a cataract and has almost no visual acuity, or when the examiner is sufficiently skilled. It is easy to measure the axial length. However, if the examiner is inexperienced or the subject's eye has sufficient visual acuity, the subject's eye may move as the probe approaches, making it impossible to accurately measure the axial length. Therefore, there is a desire to provide some choice in the driving method of the ultrasound probe depending on the patient's condition, the examiner's preference, or the examiner's skill level. An object of the present invention is to solve the above-mentioned problems, to have a detection means for stopping and limiting the drive at each position in the driving direction of the measuring system and slide table, and to have a function of selecting or changing the movement of the measuring means. The objective is to provide ophthalmological instruments with [Means for Solving the Problems] In order to achieve the above object, the ophthalmological instrument according to the present invention includes a measuring means for detecting information on the eye to be examined by contacting the cornea of the eye to be examined; An ophthalmological instrument comprising a driving means for driving in the direction of the eye to be examined, a detecting means for stopping the driving of the measuring means at a predetermined position, and an adjusting means for keeping the contact pressure of the measuring means on the cornea substantially constant, The measuring means is characterized in that the stopping position of the measuring means can be variably set at the position where it contacts the cornea, and before and after that position. [Operation] The ophthalmological instrument with the above configuration stops at any position of the measurement means that contacts the cornea of the eye being examined, and performs measurements according to the purpose. [Example] The present invention will be explained in detail based on the illustrated example. In Fig. 1, a first measurement system that measures the corneal refractive power after setting a wooden body 2 on a sliding table l at a predetermined position with respect to the eye E, and a first measurement system that measures the corneal refractive power from this position in the direction of the eye E. A second measurement system is provided for determining the ocular axial length, which includes an ultrasound probe that is moved and measures by contacting the cornea. In the first measurement system, an objective lens 3 is arranged facing the eye E, and mirrors 4, 5,
An imaging lens 6 and an image sensor 7 are arranged, and this image sensor 7
The output of is connected to the TV monitor 8. The objective lens 3, mirrors 4 and 5 are integrally constructed, and the electric motor 9
It is designed to be able to move up and down by a wire 10 driven by. Further, around the objective lens 3, for example, four light sources 11a from light emitting diodes are provided as shown in FIG.
~lid is placed. Furthermore, in the second measurement system, an ultrasonic probe l2 placed behind the mirror 4 is held by a sliding guide member 14 via a probe holder l3, and this ultrasonic probe l2 is The spring 15 serves as an adjusting means for keeping the contact pressure of the ultrasound probe 12 on the cornea of the eye E to be substantially constant. Further, the probe holder 13 can be moved back and forth by a wire 17 that is moved by an electric motor 16. Here, when the light beam from the light sources 11a-lid is projected onto the cornea of the eye E to be examined at a predetermined spatial distance, a corneal reflection image of the light sources ILa-lid is formed due to the convex mirror action of the cornea. Since the phase TL relationship of the light spot position of these corneal reflection images changes depending on the radius of curvature and degree of astigmatism of the cornea, by detecting this change, the corneal refractive power, degree of corneal astigmatism, and axial angle can be determined. It is well known that it is possible to find The first measurement system for this purpose is the light source 11a as described above.
- objective lens 3, mirror 4,
5. Detection is performed by forming an image from the imaging lens 6 onto the image sensor 7 using an optical system. This detection signal is processed in an electric circuit (not shown), and further arithmetic processing is performed to obtain corneal refractive power, corneal astigmatism, and axial angle. Note that the image sensor 7 not only detects the measurement signal, but also determines the wooden body 2 on the sliding table 1 from the imaging state of the anterior segment image with respect to the eye E to be examined, and sets it at an appropriate predetermined position. It also functions as a location confirmation method. As described above, the second measurement system includes the ultrasonic probe 12. It is composed of a probe holder 13, a sliding guide member l4, and a spring 15. The probe 12 contains an ultrasonic oscillator and a receiver, and is connected to an electric circuit (not shown) via a cable. Place the ultrasound probe 12 on the eye E to be examined.
The axial length of the eye E to the retina of the eye E is detected by emitting an ultrasonic pulse from the tip of the probe 12 while in contact with the cornea of the eye E and receiving the reflected echo from the cornea of the eye E. be able to. By measuring the corneal refractive power and axial length of the eye E in this way, the refractive power of the crystalline lens can be calculated from these values using a formula obtained empirically. In this embodiment, when measuring corneal refractive power, the ultrasound probe l2
are retracted behind the mirror 4 so as not to obstruct the optical path for corneal refractive power measurement. However, when a changeover switch (not shown) is switched to the axial length measurement mode, the objective lens 3, mirror 4,
5 is driven down by an electric motor 9 and a wire IO,
Next, the probe 12 is driven in the direction of the eye E by the electric motor 16 and the wire 17 via the probe holder 13 and the spring 15. Regarding the method of driving the ultrasonic probe l2 at this time, if the examiner is sufficiently skilled in measurement or if the eye E to be examined has almost no visual acuity, the electric motor 16 and wire 17 may be used to The axial length of the eye is measured by driving the child 12 and making direct contact with it. In addition, if the examiner's measurement technique is inexperienced or if the eye E to be examined has sufficient visual acuity, the probe 12 may be driven slightly in front of the eye E to be examined by means described later and then stopped. do. After that, while maintaining the forward view of the eye E, the wooden body 2 is gently slid toward the eye E side using the operation stick 1a on the sliding table 1, and the contact l2 is brought into contact with the cornea of the eye. Measure the axial length. In some cases, the probe 12 is kept in contact with the cornea of the eye E to be examined, the drive is stopped, and then the examiner slides the wooden body 2 to take measurements. 3 and 4 show an embodiment in which the stopping position of the ultrasound probe l2 with respect to the eye E to be examined is variable, and the probe holder 13
Three microswitches 20a, 20b, and 20c are provided that contact each other separately as the switch moves. These switches 20a, 20b, 20c are connected to electric motors 16.
are connected, and each switch 20a. 20b, 20
The circuit c is connected to the power supply by the selection switch 21. As mentioned above, the electric motor 16 and the wire 17 move the subject's eye E.
The ultrasonic probe l2, which is driven in the direction of Stops driving. For example, if the micro switch 20a is selected, the contact 12
stops +h before contacting the eye E to be examined. In addition, when the microswitch 20b is selected, the contact 12 is stopped in a state where it is almost in contact with the eye E to be examined, and when the microswitch 20c is selected, the contact 12 is made to stop when it is almost in contact with the eye E to be examined. It is pushed further forward than the position and stops in such a state that contact pressure is applied to the eye E to be examined. However, as mentioned above, the contact pressure can be kept constant by the spring 15, so that it hardly affects the measured value. In this way, in the embodiment shown in FIGS. 3 and 4 in which the stopping position of the ultrasound probe 12 with respect to the eye E to be examined is variable, three
Microswitches 20a, 20b, and 20c are installed, and they are operated by switching from the selection switch 2l.
It is also possible to make a similar contact by changing the position of one microswitch using a guide member or the like. Furthermore, if a photo sensor, magnetic sensor, etc. is used in place of the microswitch 20, the contact holder 13 can be controlled without contact, and the movement of the ultrasonic probe l2 can be made smooth. Furthermore, the same objective can be achieved by using a stepping motor as the electric motor 16 and making the number of drive pulses applied to the electric motor 16 variable. [Effects of the Invention] As explained above, the ophthalmological instrument according to the present invention can adjust the electric drive stop position of the ultrasonic probe with respect to the eye to be examined by controlling the micro switch, etc., or changing the drive pulse of the electric motor. By making the position variable, it is possible to select an appropriate position according to the convenience of the subject and the examiner, which has the advantage of improving the accuracy of measuring the axial length and shortening the measurement time.

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

図面は本発明に係る眼科器械の実施例を示し、第１図は
全体の構戒図、第２図は対物レンズと光源の配置図、第
３図は超音波探触子を前進させた状態の構成図、第４図
はマイクロスイッチの作動を説明する電気回路図である
．The drawings show an embodiment of the ophthalmological instrument according to the present invention, in which Fig. 1 shows the overall composition, Fig. 2 shows the arrangement of the objective lens and light source, and Fig. 3 shows the state in which the ultrasound probe is advanced. Fig. 4 is an electrical circuit diagram explaining the operation of the microswitch.

Claims (1)

【特許請求の範囲】 １、被検眼の角膜に接触して被検眼情報を検出する測定
手段と、該測定手段を被検眼方向に駆動させる駆動手段
と、前記測定手段を所定位置で駆動停止させるための検
知手段と、前記測定手段の角膜への接触圧をほぼ一定と
する調整手段とを備えた眼科器械において、前記測定手
段の停止位置を角膜に接触する位置及びその前後に可変
に設定可能としたことを特徴とする眼科器械。 ２、前記測定手段は超音波探触子とした請求項１に記載
の眼科器械。 ３、前記測定手段は接触型眼圧計とした請求項１に記載
の眼科器械。[Scope of Claims] 1. Measuring means for detecting information on the eye to be examined by contacting the cornea of the eye to be examined, driving means for driving the measuring means in the direction of the eye to be examined, and driving and stopping of the measuring means at a predetermined position. In an ophthalmological instrument comprising a detection means for detecting and adjusting means for keeping the contact pressure of the measuring means to the cornea substantially constant, the stopping position of the measuring means can be variably set at the position where the measuring means contacts the cornea and before and after the position where the measuring means contacts the cornea. An ophthalmological instrument characterized by: 2. The ophthalmological instrument according to claim 1, wherein the measuring means is an ultrasonic probe. 3. The ophthalmological instrument according to claim 1, wherein the measuring means is a contact tonometer.