WO2001054569A1

WO2001054569A1 - Device and method for detecting the radius or an equivalent variable of the chamber angle of an eye

Info

Publication number: WO2001054569A1
Application number: PCT/EP2000/004302
Authority: WO
Inventors: Manfred Tetz; Stephan Schruender
Original assignee: Bioshape Ag
Priority date: 2000-01-24
Filing date: 2000-05-12
Publication date: 2001-08-02
Also published as: DE10002672A1; DE10002672C2

Abstract

The aim of the invention is to select the right size of a lens to be implanted into an anterior chamber of an eye of phakic eyes. A measuring device for measuring or estimating the radius (r) or an equivalent variable of the surface which is enclosed by the circumferential line (35) of the chamber angle and is supposed to be circular is provided, whereby said line pertains to the anterior chamber (30). The measuring device (10) comprises an insertion body (12) which can be inserted into the anterior chamber (30) through an opening (36) in the cornea (31). The measuring device also comprises a detection unit (14) that is situated on the insertion body (12) or is functionally coupled therewith and is configured in such a way that the relative position of at least two points of said surface, especially the distance thereof, can be detected. Said radius (r) or the equivalent variable can be deduced from said relative position. The invention also relates to a method for measuring the radius (r) or the equivalent variable according to the invention.

Description

Device and method for determining the radius or an equivalent size of the chamber angle of an eye

The invention relates to a measuring device and a method for measuring or estimating the radius or a size equivalent to the radius of the substantially circular surface enclosed by the ventricular angle line of the anterior chamber of an eye.

In recent years, refractive surgery has been predominantly dominated by excimer laser surgery. While it quickly became clear that PRK (photorefractive keratectomy) is unsuitable for high myopia, LASIK (laser in situ keratomileusis) initially had the hope of being able to use it to correct even the highest myopia satisfactorily. In the meantime, however, a certain disillusionment has occurred. With myopia of more than 10 dpt. the spread of the refraction results is already increasing significantly. In addition, the treatment zones are too small for the laser in relation to the size of the pupil, which can then lead to problems, particularly at dusk and in younger patients with a pupil that can be dilated well. A further anatomical limitation arises from the fact that if the residual corneal thickness falls below 50 percent of the initial value, the risk of corneal ectasia (bulging due to mechanical instability) increases significantly.

Against this background, interest in the higher myopias has increasingly turned to lens surgery in recent years. In addition to the long-known process of extracting the clear lens and their replacement with an intraocular lens, several authors have recently reported about their experiences in implanting intraocular lenses into phakic (capable of accommodating) eyes

This is also an older procedure in principle. Strampelli and Barraquer in the 1950s tried to correct high myopia by implanting artificial lenses in phakic eyes. Despite some encouraging results, the overall compliance rate was so high that this approach initially was abandoned

However, thanks to improved lens materials and the use of modern aids, in particular viscoelastics, which protect the endothelium of the cornea by stabilizing the anterior chamber, there has been a certain renaissance in the implantation of intraocular jackets in phakic eyes in recent years Target refraction is currently somewhat worse than that of the PRK and LAS IK procedures. However, such statements must take into account that phakic intraocular lens implantation is currently recommended by most surgeons for refractive errors where the accuracy of the other right - Active surgical procedures are also relatively low

The range of indications for the lenses presented below is seen in myopia from - 7 to - 20 dpt and in hyperopia from + 5 to + 10 dpt.However, it must be taken into account, in particular in the case of the higher hyperopia, that relatively high conditions prevail in the front section of highly hyperoperative eyes, especially in patients With already limited accommodation, some surgeons therefore give priority to the extraction of the clear lens and its replacement by conventional intraocular necks. Another indication for the implantation of intraocular necks in real eyes can be the correction of high-grade astigmatisms toric lenses available Currently, very different intraocular lens models are used, with both posterior chamber lenses, iris lenses and anterior chamber lenses being used.

Posterior chamber lenses for implantation in phakic eyes are still relatively new. These are thin, soft intraocular sleeves that are implanted into the sulcus ciliaris through the dilated pupil in front of the natural lens.

The Worst Iris Claw lens, which is also suitable for implantation in phakic eyes, is a biconcave intraocular lens made of PMMA, which is fixed in the middle peripheral immobile part of the iris by means of a claw-shaped haptic.

Anterior chamber lenses, in the field of which the present invention is located, are inserted into the anterior chamber after a cut in the cornea and clamped in the chamber angle. Fig. 1 shows such a lens from Bausch & Lomb, which is known under the name "NuVita". The advantage of the anterior chamber lenses is considered to be the technically relatively easy implantation. A potentially dangerous contact with the still existing natural lens can also be avoided in the case of anterior chamber lens implantation. The complications of the cornea feared in earlier models, particularly in the sense of progressive decompensation due to endothelial cell loss on the inner side of the cornea, seem to have been eliminated in the newer anterior chamber models. They can be designed to be flexible and therefore can also be implanted in the anterior chamber using small incision technique through corneal incisions with a diameter of approximately 3.5 mm, for example. If rigid lenses are used, the cutting diameter is e.g. 5 mm. In both cases, the induction of surgical astigmatism can usually be avoided.

Anterior chamber lenses can also be used in aphakic eyes. Here they take over the function of the eye lens. In aphakic eyes, due to lentil lens more space available, so that the spatial conditions favor the use of intraocular tubes.

The diameter of the anterior chamber in the area of the chamber angle is generally between 10 and 13 mm. The size of the implanted lenses, on the other hand, is typically 0.5 - 1 mm larger in order to avoid dislocation or rotation. The size of the lens used is currently estimated by measuring the limbus diameter (transition from cornea to sclera). In this case, the diameter is estimated from the outside by means of a measuring circle by measuring two opposite points of the cornea-dermis transition (so-called white-to-white measurement) and 1 mm is added to this distance in order to ensure that the To ensure intraocular lens in the anterior chamber. However, this estimate is naturally relatively imprecise. Therefore, disadvantageously, when using anterior chamber lenses, there is often irritation of the chamber angle, which can result in an increase in the outflow resistance of the aqueous humor, which increases the intraocular pressure (glaucoma). Various authors have also reported on the so-called ovalization of the pupil, which can be caused by incorrectly adjusted lens diameters. Mechanical forces caused by the edge of lenses that are too large in the chamber angle are responsible for the ovalization of the pupil. The irritation states in the chamber angle are primarily caused by lenses that are too large and their contact pressure.

Despite this deficiency, alternative measurement methods for estimating the geometric conditions of the anterior chamber have not been found.

It is an object of the present invention to further develop a device and a method of the type mentioned at the outset in order to achieve a more precise assessment of the geometric conditions in the anterior chamber so that more accurate anterior chamber lenses can be inserted into the anterior chamber of phakic or aphakic eyes. The object is achieved in the device of the type mentioned above in that the device comprises an insertion body, which can be inserted through an opening in the cornea into the anterior chamber, and a determination unit functionally coupled to the insertion body or to the insertion body, which is designed in this way that the relative position of at least two points of the aforementioned surface, in particular their distance, can be determined, it being possible to infer the radius or an equivalent size from this relative position.

This object is achieved in the method of the type mentioned at the outset in that this method comprises the following steps: an opening is cut into the cornea; an insertion body of a measuring device is inserted through the opening into the front chamber; and the relative position of at least two points of the said surface, in particular the distance thereof, is determined with the aid of the insertion body in such a way that it is possible to infer the said radius or the equivalent size from this relative position.

The advantages of the invention can be seen in particular in the fact that it is possible by means of the method or the device presented to advance a suitable measuring instrument through the opening in the cornea, through which the lens should preferably be subsequently introduced, into the anterior chamber. From the determination of the relative position of at least two points of the area enclosed by the chamber angle circumference line, the radius of the anterior chamber can then be deduced in a known manner - for example using simple geometric formulas or in the simplest case by reading directly from a scale. It is assumed that the chamber angular circumference defines an arc. Deviations from this circular arc shape are essentially negligible and are therefore not taken into account. By means of the device and method according to the invention, no imprecise estimation from outside the More eye marks, the radius or the equivalent size can be measured directly without any obstacles in the way - in the case of measurements from the outside, this is the cornea

In the following, the term "radius" is generally used instead of "radius or an equivalent size", the term also includes the equivalent sizes mentioned. The term "equivalent size" also includes, for example, the determination of the distance from a point of the To understand the chamber angle to a point on the axis of symmetry of the eye that is not the center of said circular area. This distance is related to said radius via simple trigonometric functions - such as the sine or cosine function

The determination of the at least two points mentioned can be determined, for example, by means of optical and / or acoustic methods (reflection or absorption measurements, transit time measurements) and / or mechanical methods. For the first-mentioned type of measurements, for example, a light or sound transmitter and / or a is on the import body Light or sound receiver arranged If the transmitter and receiver are placed, for example, on the axis of symmetry of the circle enclosed by the chamber angular circumference, the radius can be deduced from the transit time of the signal reflected at the chamber angle. In general, such measurements allow much more precisely than in the prior art Determine the radius (or the diameter or another equivalent size) of the area enclosed by the chamber angle circumference and use these values to select the optimal anterior chamber lens for implantation

In general, it can be said that the radius or the equivalent size can be determined by the determination unit depending on the position of the import body in the front chamber Preferably, the determination of the relative position of the points consists of the determination of their distance.For example, it is sufficient to determine the distance between two points, e.g. the center of the circular area enclosed by the circumferential angle of the chamber and a point on the circumferential angle of the chamber (or - more simply - that Chamber angle) The relative position of the two points is thus equivalent to the radius sought. Alternatively, the distance from two points is measured on or near the chamber angle orbit, the direct connection of which runs through the mentioned center point and which thus describes the diameter of the chamber angle orbit Define circular area For example, the distance from the opening of the cornea to the opposite chamber angle section can be determined and - to improve the measurement accuracy with optional consideration that the opening in the cornea for spatial reasons above the chamber angle It must lie - conclude from the diameter of the ventricular angular circumference

It should be noted that in the entire application "center point" and "point on the chamber angular circumference" does not necessarily mean the ideal position in the center or on the chamber angular circumference, points with slight deviations from the center point or from the chamber angular circumference also fall under the aforementioned terms

Alternatively or in addition, the side length of an isosceles triangle, essentially in the area enclosed by the chamber angular circumference, is determined, of which two corner points lie on the chamber angular circumference and the third corner point lies on or near the said center point and thus the leg length of the triangle is equal to that Radius searched for This three-point measurement increases the measuring accuracy compared to the previously described two-point measurement, consisting of measuring the distance from the center of the circular area enclosed by the chamber angle circumference to a point on the chamber angle circumference The determination unit is preferably designed in such a way that the radius or the equivalent size can be determined via the determination unit due to the position of the insertion body in the front chamber.

The measuring device advantageously has an insertion body designed as a measuring rod. This is preferably introduced eccentrically through the cornea into the anterior chamber and advanced through the anterior chamber in such a way that the insertion body is in a feed position substantially above and preferably close to the center of the circular area delimited by the chamber angular circumference and with the chamber angle section opposite the cornea opening at least one point in contact or as close as possible to that point. The said radius can then be determined according to the possible advance of the insertion body via a determination unit arranged on or coupled to the insertion body, the determination unit advantageously comprising a reading or display unit. If the determination unit is located outside of the said center on the axis of symmetry of the eye, corrections are necessary for accurate measurements in order to take into account the angle between the circular area enclosed by the chamber angle circumference line on the one hand and the connecting line between the determination unit and the point of contact of the chamber angle on the other hand. This can already be taken into account when calibrating the determination unit; The opening in the cornea in the different eyes should then advantageously be incised in the same place, if possible, in order to find approximately the same angular relationships in each case.

Particularly preferably, the said radius of the area enclosed by the chamber angle circumferential line or the said equivalent size through the cornea can be read by the determination unit when the insertion body is in a feed position in contact with the chamber angle. For this purpose it is provided in a particularly advantageous embodiment of the invention that the determination unit as a scale on the Introducer body is formed and that a light beam from outside the anterior chamber along the axis of symmetry of the eye - which intersects the center of the circular area delimited by the chamber angular circumference - is radiated onto the scale and generates a readable signal there. Advantageously, the light beam is reflected on the scale division in such a way that the value can be read directly from the section of the scale at which the light beam strikes. For this it is sufficient that the scale has, for example, ten graduation marks, without the numbers or the like necessarily being applied to the scale. The operator of the measuring device can infer the radius from the position of the light beam on the scale alone. The individual graduation marks can also be designed differently (for example, different lengths) in order to achieve an exact assignment.

The scale is preferably calibrated in such a way that the radius of the approximated circular area can be read directly and, based on this value, the suitable lens for implantation can be selected quickly and inserted into the anterior chamber through the opening in the cornea after removal of the measuring device. When calibrating, it can be taken into account that, in the measuring position, the scale is not arranged entirely in the area defined by the chamber angular circumference, but mostly above.

Instead of radiating a light beam directly onto the scale, an advantageous further development provides for the cornea to be marked at the point intersecting the axis of symmetry. For this purpose, for example, a metal tip is placed on a guide above the cornea on the axis of symmetry or the optical axis of the eye and the cornea is scored with this metal tip. A light beam is then directed centrally along the axis of symmetry of the eye to this marked point, so that the marking is shown on the scale and the radius can be read using this signal.

Alternatively or additionally, a semiconductor is provided on the insertion body, which is a location-dependent one depending on the point of impact of the incident light beam generates an electrical signal, which is passed via a line from the front chamber to an evaluation and display unit. This line expediently runs in or along the import body

As an alternative or in addition, the determination unit of the measuring device is designed as a scale that cuts the cornea, for example, when the measuring device is in the maximum advanced position, so that the diameter or the radius - depending on the calibration of the scale - can preferably be read at this interface with the naked eye When calibrating, it should advantageously be taken into account that the opening in the cornea does not lie on the circumferential angle of the chamber, but lies above it. In an advantageous embodiment of the measuring device, when the introducer is in the measuring position, both in the region of the said center of the chamber angular circumference and scales provided in the area of the insertion body which intersects the cornea opening

Advantageously, the emptying body has a shape that allows it to be introduced into the front chamber in an elongated configuration. For this purpose, the embodying body either inherently has such an elongated shape or can be brought into such a shape, for example by folding or other volume reduction

At least two formations are preferably arranged at the distal end of the insertion body, which simulate the foot plates of known anterior chamber sockets. In this way, not only can the future position of the intraocular lens in the anterior chamber be estimated, but the measurement accuracy can also be measured increase the additional contact of the import body with another ventricular angle point

The measuring device advantageously consists of at least one proximal and one distal part, which are arranged at an angle to one another. In a measuring position of the measuring device, this is in the anterior chamber advanced that the distal part is on the axis of symmetry - in a preferred embodiment, preferably at a short distance above the center - of the circular area enclosed by the chamber angular circumference or intersects this center. In this advanced position of the measuring device, the proximal part points away from the eye lens and protrudes through the opening in the cornea to the outside in order to pass there into a handle body for, for example, manual handling of the measuring device. By means of this configuration it is possible, on the one hand, to implement simple handling of the measuring device on the one hand, and on the other hand, to be relatively accurate Measurements to be carried out, since the body of the emporter and in particular the scale is arranged essentially close to or in the area defined by the circumferential angle of the chamber angle. However, if the body of the emporter is linearly stretched, the trigonometric relationships must be be taken into account, since the body of the emporter is then at a larger angle to the surface in the anterior chamber enclosed by the peripheral chamber angle

In order to achieve as little traumatizing measurement as possible, in a particularly advantageous embodiment the body of the emporter has a flat distal end. This reduces the risk of injury to the sensitive endothelial layer on the inner corneal side

In an advantageous development of the invention, the embodying body is formed at least as consisting of two mutually movable parts. A pivoting arrangement is articulated on a base body of the insertion body that is elongated in advance, which is essentially pivotable in the area defined by the circumferential chamber angle so that it adjusts the chamber angle touches at least two spaced-apart points. For this purpose, the swivel arrangement can be essentially rod-shaped, for example, so that in the pivoted position it spans a cross with the base body. The two free ends of the swivel arrangement touch the chamber angle at different sections The above described guide body with the rod-shaped swivel arrangement can be used to measure said radius in two ways. In the folded state, ie the swivel arrangement is essentially flush with the base body, the free end of the swivel arrangement pointing in the direction of advance protrudes over the free end of the base body out and touches - in a first measuring position of the measuring device - in a maximum feed position the chamber angle. In this position of the insertion body, the radius can be read from the cornea by means of the aforementioned light beam from a first scale on the base body or the swivel arrangement

For the second measurement, which serves as a control measurement, for example, the body of the emporter is withdrawn, but remains in the front chamber. The swivel arrangement can then be pivoted - advantageously by means of leverage, i.e. force that is eccentrically offset with respect to the axis of rotation by means of pulling or pushing The end of a rigid wire is eccentrically connected to the swivel arrangement. The wire runs along the base body and out of the eye through the opening in the cornea. By pulling or pushing on the free end of the wire protruding from the eye, the swivel arrangement can be swiveled into its second measuring position and to pull the import body out of the front chamber again into its original import position. If the swivel arrangement is swiveled into its measuring position, ie the swivel arrangement protrudes vertically from the base body, the body of the emporter is again proposed in this way choben that the free ends of the swivel assembly each touch the chamber angle. Make sure that the base body is above the center of the circle defined by the chamber angle circulation

The base body has a second measuring scale for reading said radius, which is as close as possible in this second measuring position of the import body Located above or in the center of the chamber angular orbit and which is preferably calibrated in such a way that the radius can again be read directly. When the measuring device is advanced, the second measuring scale can either be located in the area of said center point and / or also at the entry of the measuring device into the front chamber.

So that the swivel arrangement does not swivel beyond the 90 ° position and thus remains in its position perpendicular to the base body during the measurement, a stop can be provided on the base body and / or the swivel arrangement, which prevents further swiveling.

In an alternative embodiment of the invention, the distal end of the insertion body has a loop which, when the measuring device is advanced into the front chamber, is designed to be extendable and retractable and partially extends into a section of the chamber angle when extended. The radius can be determined from the length of the loop on the one hand and from the position of the scale in the front chamber on the other hand, since the loop lies in the chamber angle in a predetermined and reproducible manner due to its material properties. In a preferred embodiment, the distal end of the insertion body is designed as a tube. In order to limit the movement of the loop when it is applied in the chamber angle, the distal end of the insertion body can have two legs which can be folded out at a defined angle, so that two opposite loop sections in the maximally extended, ie advanced state of the loop on the opened legs of the insertion body and place the loop section connecting the two loop sections against the chamber angle section opposite the two legs. In this way, a maximum feed position is defined for the insertion body, from which the radius (r) or an equivalent size can be determined, for example by means of the scale intersecting said axis of symmetry in the feed position. Due to the multi-point contact of the loop with the chamber angle, a high measuring accuracy can be achieved. For an accurate determination of the radius, the correct position of the import body in the anterior chamber is essential for all embodiments of the invention. In the embodiments of the invention described above, for example, the body of the emporter or the base body must have the axis of symmetry of the anterior chamber (simultaneously the axis of symmetry of the cornea and the eye ) cut To control this position, light is advantageously radiated onto the cornea by means of an illumination device opposite the cornea, in order to infer the position of the insertion body in the anterior chamber on the basis of the light reflections on the cornea and on the lens. For this purpose, a ring light is advantageously used , which is arranged essentially symmetrically with respect to the cornea. The body can thus be centered in the anterior chamber in such a way that it crosses the axis of symmetry of the anterior chamber. A centrally illuminating light source can also be used ne point-shaped reflex generated As an alternative to this - as already described above - a marking is applied in the center of the cornea, light is radiated along the axis of symmetry and the body is positioned in the anterior chamber in such a way that the marking is imaged on the body or on its scale

In a further preferred embodiment of the invention, the sensor body has an elongated base body and at least two sensors which are movable relative to the body body.These sensors can be extended in opposite directions when the body is inserted into the front chamber, whereby they slide into the respective chamber angle section aligned that their direct connecting line runs through the axis of symmetry of the circular surface enclosed by the chamber angular circumference. In this way, the diameter of said surface is obtained

A special embodiment for this alternative embodiment provides that the base body is hollow and its distal end is divided into two in opposite directions pipes passes with openings from which wires can be extended, at the ends of which a sensor is arranged. If the tubular elements are curved, the sensors can be guided in these opposite directions.

In order to move the sensors relative to the base body, a push / pull device or a screw device is advantageously formed in the region of the proximal end of the base body, which is coupled to the sensors, for example, via the wires mentioned. An operable part of the pushing / pulling device or the screwing device preferably protrudes from the cornea. The amount of advance of the sensors in the front chamber can be adjusted by pushing / pulling or screwing. In the case of a screwing device, the wires are guided in a sleeve so as to be longitudinally displaceable (for example with a worm thread), the sleeve preferably having an eye thread which is in screw engagement with an internal thread of the base body. If the sleeve is screwed out of the base body or screwed further into the base body, the wires are inserted into the base body or further out of it.

The diameter detected by the sensors is preferably read from a determination unit designed as a scale, the scale being arranged on the push-pull device or the screw device. The scale is arranged, for example — outside the cornea in the transition region to the tube of the base body — in the inserted state of the insertion body. The diameter can then advantageously be read from the measure of the advance of the scale.

When using the latter device, it is pushed into the front chamber in such a way that the two openings of the base body are as close as possible to the center of the circle enclosed by the chamber angular circumference, then the sensors are extended and preferably the insertion body when the sensors are extended in this way is pushed back and forth until the sensors are at a maximum distance from each other. Here- at the sensors are also conveniently always pushed back and forth so that they can always detach themselves from the chamber angle. In the maximum extended state, the two sensors measure the diameter of the said circle.

Further advantageous developments of the invention are characterized by the features of the subclaims.

Four exemplary embodiments of the invention are explained in more detail below with reference to the drawing. Show it:

1: a known anterior chamber lens;

2 shows a cross section through an eye with a first embodiment of the invention in a front chamber in the maximum advanced position;

3: a plan view of the measuring device according to FIG. 2;

4: a plan view of a modification of the first embodiment of the invention with two distal projections;

5: a schematic plan view of a second embodiment of the invention with a swivel arm in the folded state in the maximum advanced position (first

Measuring position);

6: a schematic plan view of the measuring device according to FIG. 5 in the pivoted state and in the maximally advanced position (second measuring position); and 7 shows a thematic top view of a third embodiment of the invention with an extendable loop in the maximum advanced position.

Fig. 8: a schematic plan view of a fourth embodiment of the invention with two extendable sensors in the maximum advanced position.

1 shows a known front chamber lens 1 with the name "NuVita" from Bausch & Lomb. A lens body 2 is provided centrally, which has two curved arms 4 on two opposite edge regions, which are supported on footplates 3 during implantation in a front chamber in the chamber angle. The anterior chamber lens 1 is designed to be elastic so that it can be inserted into the anterior chamber through a small opening in the cornea in the compressed state.

The structure of the schematically illustrated eye is shown briefly with reference to FIG. 2. The anterior chamber 30 is delimited from the outside world by the cornea 31, which has a mechanically very sensitive endothelial layer on its side facing the anterior chamber 30 (not shown). The anterior chamber 30 is delimited towards the inside of the eye by the iris (also known as the iris) 32 with the pupil 33 lying centrally and the lens 34 arranged underneath. The circumferential section in which the cornea 31 and the iris 32 meet is the chamber angle or the chamber angle circumference 35.

The measuring device 10 according to FIG. 2 (shown in the advanced state in the front chamber 30) and FIG. 3 is designed as an angled rod and has a narrow handle body 11 and a narrow insertion body 12. The insertion body 12 is divided into a proximal section 12a and a distal section 12b, which are angled to one another. The free end 13 of the distal section 12b - at the same time the distal end of the measuring device 10 - runs out narrow and flat This end 13 is preferably rounded in such a way that its radius of curvature is smaller than the radius of the essentially circular chamber angular circumference 35. The distal part 12b of the insertion body 12 has a scale 14, which is divided, for example, into half millimeter intervals and A scale 14a is additionally provided on the proximal part 12a with appropriate illumination from the outside of the eye with appropriate lighting. In one embodiment of the invention, not shown, only one of the two scales 14, 14a is provided

To use the measuring device 10 shown in FIG. 2, an opening is cut eccentrically into the cornea 31 and the body 12 - while holding the grip body 11 - through the opening 36 formed in the cornea 31 into the anterior chamber 30 and until its narrow distal end is touched 13 advanced with the chamber angle 35 opposite the opening 36, without touching the endothelial layer on the inside of the cornea 31 as far as possible. The body 11 still protrudes from the opening 36. In this position, the scale 14 is as close as possible to the center 20 the area described by the chamber angular circumference 35, the radius r or diameter of which is ultimately to be determined. In this way, both the distal end 13 and the scale 14 are essentially in the circular plane enclosed by the chamber angular circumference 35, so that measurement errors in the radius determination are due to from Hoh The overall width of the scale 14 is chosen such that both unusually small and large anterior chamber radii r can be determined

According to FIG. 2, the scale 14a on the proximal section 12a of the insertion body 12 is in the advanced state of the measuring device 10 in the region of the opening 36 of the cornea 31 and is taking into account the angular conditions (because of the position of the opening 36 above the chamber angular circumference line) 35) is calibrated such that the radius r or the diameter can also be read from this scale 14a The most accurate possible position of the insertion body 12 in the anterior chamber 30, namely as precisely as possible above the center 20 of the chamber angular circumference 35, can be achieved in that light from an illumination device (not shown) arranged opposite the cornea 31 is radiated onto the eye, for example from a ring light. The position of the insertion body 12 in the anterior chamber 30 can then be checked by observing the reflexes on the cornea 31 and / or on the lens 34. In addition, a centrally illuminating light source with a small beam diameter can be used, which generates a point-like reflection in the center of the front chamber.

To read the radius r from the scale 14, a light beam is preferably radiated onto the scale 14 from outside the eye along the axis of symmetry 37 of the anterior chamber 30 or the eye, which intersects the center 20 of the circular area enclosed by the circumferential chamber angle 35. This light beam is reflected on the scale 14, the point of impact on the scale 14 can be observed through the cornea 31, possibly with the aid of a deflecting mirror for the reflected beam. In this way, an extremely easy yet precise reading of the radius r is possible.

Alternatively, a ring light is used that emits a light beam with an annular cross-section along the axis of symmetry through the cornea and is not used (only) to adjust the position of the insertion body in the anterior chamber, but to read the radius from the scale. The radius can be inferred from the points of impact of the ring beam.

Furthermore, alternatively, the cornea 31 is incised at its intersection with the axis of symmetry 37. For this purpose, for example, a metal tip on a guide is used, which is arranged centrally above the cornea (not shown). Alternatively, a mask (not shown) with a central hole is placed over the cornea 31 and the corneal area aligned with this hole is cut marked - for example by tiny scratches. In all cases, a light beam is directed along the axis of symmetry 37 of the eye to the marked point. The marking is thereby mapped onto the scale 14 and the radius r can be read off.

Depending on the design of the scale 14, the reflected or observed signal is different. Instead of a conventional scale division, holes (not shown) can also be provided along the scale division. If the holes continuously become smaller in one direction and the light beam with a defined diameter can therefore pass through these holes to different degrees at different radii r of the front chamber 30, the radius r can be concluded from the reflected signal.

In the modification shown in FIG. 4 of the first embodiment of the invention shown in FIGS. 2 and 3, the distal end of the insertion body 12 has two projections 13a, which the shape of the foot plates 3 of the anterior chamber lens 1 shown in FIG. 1 and thus the To simulate the seat of this lens to be implanted. At the same time, the two projections 13a give the insertion body 12 a more stable position in the chamber angle 35 during the measuring process.

In the second embodiment of the invention according to FIGS. 5 and 6, the measuring device 110 again consists of a handle body 11 (not shown in the top view of FIGS. 5 and 6) and an insertion body 112, which in this case consists of two movable parts Share is trained. The insertion body 112 in this case has a base body 115 and a pivoting arrangement 116 articulated on its distal end, which in the exemplary embodiment shown is rod-shaped and can be pivoted essentially in the plane defined by the chamber angle circumference line 35. Furthermore, the base body 115 has two scales arranged next to one another, a distal, first scale 114 and a proximal, second scale 11 The length of the rod-shaped swivel arrangement 116 is selected such that it does not cover the first scale 114 with the base body 115 when in alignment. Alternatively, the first scale 114 is arranged on the swivel arrangement 116 which is long enough.

The measuring device 110 according to the second exemplary embodiment is brought into a position for insertion into the front chamber 30 through the opening 36, in which the base body 115 and the swivel arrangement 116 are aligned with one another. For a first measurement, the measuring device 110 is then advanced against the chamber angle 35 opposite the opening 36, taking care that the base body 115 intersects the axis of symmetry 37 of the anterior chamber 30 (which coincides with the optical axis of the eye) and the first scale 114 is thus close above or on the center 20 of the ventricular angle rotation (FIG. 5). Then - as described for the first exemplary embodiment - the radius r can be read from the first scale 114 by irradiating a light beam. Alternatively or additionally, a scale is provided at the opening 36 (see the exemplary embodiment described first).

A control measurement or also an independent measurement by means of the measuring device 110 according to FIGS. 5 and 6 is possible if the measuring device 110 is pulled back a little from the chamber angle 35 and the swivel arrangement 116, for example by means of a wire (not eccentrically articulated with respect to the swivel axis 117) shown), which engages the swivel arrangement 116 and is guided out of the front chamber 30 through the opening 36 along the measuring device 110. 6 shows that the pivoting arrangement 116 has been pivoted by 90 ° in the second measuring position relative to the base body 115 and then advanced again against the chamber angle 35 so that the free ends 118 of the pivoting arrangement 116 lie against the chamber angle 35 , In this case, the second scale 119 lies above said center point 20 on the axis of symmetry 37 of the eye. The second scale 119 is calibrated in such a way that the radius r sought can also be read directly from it. Such a calibration obeys simple geometric laws, since in the end the side lengths of an isosceles triangle are determined, from which two corner points on the circumferential angle 35 of the chamber and the third corner point the center point 20 of the chamber angular circumference 35 and thus the length of the legs corresponds to said radius r. The second scale 119 can accordingly be calibrated according to simple and known geometric formulas

To pull out the measuring device according to FIGS. 5 and 6, the swivel arrangement 116 is brought back into the position aligned with the base body 115

FIG. 7 shows a third exemplary embodiment of the invention. The principle of operation is similar to that of the exemplary embodiment according to FIGS. 5 and 6. In the measuring device according to FIG. 7, the distal end of the insertion body 212 can be folded out in the longitudinal direction into two legs 212a, which extend For example, let it fold out only up to a maximum angle α by means of a stop. The body 212 is hollow in shape. A loop 216 is arranged inside it, which can be extended or retracted, for example, by pressure or tension. The body 212 is in the folded state the leg 212a has been inserted into the front chamber 30, the loop 216 is extended, causing the legs 212a to spread. In the maximally extended state of the loop 212a, on the one hand it lies on the inside of the legs 212a and on the other hand - with appropriate advancement of the insertion body 212 - on the Kammerwin opposite opening 36 The section of the loop 216 is selected in such a way that it cannot penetrate into the relatively narrow space between the free ends of the legs 212a and the chamber angle circulation - never 35. From the maximum feed position of the import body 212 can then be on the scale 214 in the way described above determine the radius r. When the loop 216 is retracted, the legs 212a fold again, for example caused by a spring acting between them accordingly; alternatively, the legs 212a are pressed together with the loop 216 retracted when the insertion body 212 is pulled out of the front chamber 30 through the narrow point of the opening 36.

In the fourth embodiment of the invention shown in FIG. 8, the insertion body 312 has a tubular base body 315 which ends at its distal end in two curved, oppositely hollowed-out tube pieces 315a with openings 315b. The tube pieces 315a can be designed to be elastic to a certain degree in order to facilitate insertion through the opening 36. A flexible, at least two-wire wire 316 runs as part of the insertion body 312 within the base body 315, sensors 313 being arranged at the free end of each wire 316, which are formed slightly fanned out in the exemplary embodiment shown. The respective other free end of the wires 316 is led out of the tubular base body 315 outside the cornea 31. A scale 314 is arranged on the wire in this area. The sensors 313 can be moved into or away from the chamber angle 35 by pushing or pulling on the wires 316, the wires being guided in the base body 315 and in particular in the tube pieces 315a. This embodiment represents a simple push / pull device. The at least two wires 316 are preferably connected to one another in the region of the proximal end of the base body 315 (not shown), so that the sensors 313 can be moved back and forth to the same extent. The wires 316 are loose at their distal end so that they can be passed through the respective opening 315b.

In order to measure the radius or the diameter of the said circular area with this embodiment, the measuring device 310 is passed through the opening

36 advanced into the front chamber 30 so that the two openings

315b of the base body 315 as close as possible in the area of the center 20 of the of the circle enclosed by the chamber angular circumference line 35. The aim is to extend the two sensors 316 to the maximum, since they represent the diameter in this position. Accordingly, by pushing the interconnected wires 316, on the one hand the sensors 313 are extended and, expediently, the base body 315 is pushed back and forth in the insertion direction at the same time until the sensors 316 are at a maximum distance from one another, which is also the desired diameter. The diameter can then be read off the scale 314 and there preferably on the edge of the base body 315. In this case too, the scale 314 can be calibrated according to the height offset relative to the said circular area.

In an alternative embodiment of the fourth embodiment, not shown, the wires 316 are connected to a screwing device, for example a sleeve which is mounted in the base body 315 and can be rotated about its longitudinal axis. The stamp has, for example, an external thread and the base body 315 has a correspondingly designed internal thread. By rotating the plunger - on which the scale 314 can be arranged in the area of the thread - the sensors 316 can then be moved in and out.

Based on the above measurements, a more precise selection of a lens to be fitted in the anterior chamber is possible.

Claims

P A T E N T A N S P R Ü C H E

1. Measuring device for measuring or estimating the radius (r) or a size equivalent to the radius of the essentially circular surface enclosed by the chamber angular circumference (35) of the anterior chamber (30) of an eye, comprising an insertion body (12;

112; 212; 312), which can be inserted into the anterior chamber (30) through an opening (36) in the cornea (31), and a determination unit (14, 14a; 1 14, 1 19; 214; 314) on the insertion body (12; 1 12; 212; 312) or functionally coupled to the insertion body, which is designed such that the relative position of at least two points of said

Area, in particular the distance between them, can be determined, it being possible to infer the said radius (r) or an equivalent size from this relative position.

2. Device according to claim 1, characterized in that the insertion body (12; 1 12; 212; 312) is designed such that it has a substantially elongated shape or can be brought into such.

3. Device according to claim 2, characterized in that the distal

End of the insertion body (12) has at least two projections (12a), which are modeled on the shapes of the base plates (3) of a front chamber lens (1) to be inserted.

4. Device according to one of the preceding claims, characterized in that the insertion body (12; 1 12; 212) consists of at least one proximal section (12a) and a distal section (12b) which are arranged at an angle to one another and wherein the distal Part (12b) in a measuring position of the measuring device (10, 110, 210) intersects the axis of symmetry (37) of the circular area enclosed by the angular chamber circumference (35), while the proximal part (12a) in this measuring position from the eye lens (34) or Rainbow skin (32) protrudes out of the opening (36) and into one

Gnffkorper (11) passes over

Apparatus according to claim 4, characterized in that the determination unit (14, 14a, 114, 119, 214, 314) has a first scale (14, 14a, 114, 214) arranged on the guide body (12, 112, 212, 312) .

314)

Device according to one of the preceding claims, characterized in that the scale (14, 14a) in the region of the opening (36) of the cornea (31) or above or in the center (20) of the

Kammerwinkelumlaufhnie (35) limited circular area is when the Emfuhrkorper (12, 1 12, 212) is in a measuring position advanced against the chamber angle (35)

Device according to one of the preceding claims, characterized in that the body (12, 1 12, 212, 312) has a flat distal end (13, 1 13, 313) in order to minimize the contact with the chamber angle which is as traumatizing as possible (35)

Device according to one of the preceding claims, characterized in that the embodying body (1 12) has a base body (1 15) and a swivel arrangement (1 16) articulated on the base body (1 15) which are defined in the chamber angular circumference (35) The surface can be pivoted in such a way that it touches the chamber angle (35) at least at two spaced apart points

9. The device according to claim 8, characterized in that the pivot arrangement (116) is substantially rod-shaped and in a second measuring position perpendicular to both sides of the base body (115) protrudes such that the free ends (113) of the pivot arrangement (116) touch the chamber angle (35).

10. The device according to claim 8 or 9, characterized in that the insertion body (1 12) has a second scale (1 19), which in the second measuring position of the measuring device (1 10) in the region of the opening (36) Cornea (31) is located or intersects the axis of symmetry (37) of the circular area enclosed by the chamber angle circumference line (35) and from which said radius (r) or the equivalent size can be read.

1 1. Device according to one of the preceding claims, characterized in that the pivot arrangement (1 16) is pivotable by means of pulling or pushing eccentrically offset force action relative to the pivot axis (1 17).

12. The device according to one of claims 1 to 7, characterized in that the distal end of the insertion body (212) has a loop (216) which can be extended in a defined angular range (α) of the chamber angular circumference (35), the loop being extended at the maximum extent (216) places a loop section in a chamber angle section and thereby defines a maximum feed position for the insertion body (212), from which the radius (r) or an equivalent size can be determined.

13. The apparatus of claim 1 or 2, characterized in that the insertion body (312) has an elongated base body (315) and at least two relative to the base body (315) movable sensor (31 3), the in the measuring position of the insertion body (312) can be extended in opposite directions and slide into the chamber angle, the imaginary straight line connecting the two sensors (313) intersecting the axis of symmetry (37) of the circular area enclosed by the chamber angle circumference (35).

14. The apparatus according to claim 13, characterized in that the base body (315) is hollow, that the base body (315) has two openings (315b) pointing away from each other by 180 ° and that the two sensors (313) each at the free ends of wire-shaped, in

Base body (315) guided elements (316) are attached, which are arranged to extend and retract from these openings (315b).

15. The apparatus according to claim 13 or 14, characterized in that in the region of the proximal end of the base body (315) a push-pull device or a screw device is formed, which is coupled to the sensors (316) relative to the sensors (316) to move to the base body (315).

16. The apparatus according to claim 15, characterized in that the preferably designed as a scale (314) determining unit (314) is arranged on the push-pull device or the screw device.

17. Device according to one of the preceding claims, characterized in that the scale or scales (14, 14a; 1 14, 1 19; 214; 314) are calibrated in such a way that the radius (r) of said surface can be read directly can be.

18. A method for measuring or estimating the radius (r) or a size equivalent to the radius (r) of that of the chamber angular circumference

(35) of the front chamber (30) of an eye, essentially Chen circular ^" pool, in particular by means of the measuring device according to claims 1 to 17, comprising the following steps: an opening (36) is cut in the cornea (31); an insertion body (12; 112; 212; 312) one Measuring device (10; 110; 210; 310) is inserted through the opening (36) into the front chamber (30) and the relative position of at least two points of said surface is determined with the aid of the insertion body (12; 112; 212; 312) , especially theirs

Distance, determined in such a way that the relative radius (r) or the equivalent size can be inferred from this relative position.

19. The method according to claim 18, characterized in that by measuring the contact of the insertion body (12; 1 12; 212; 312) with the chamber angle circulation line (35) the distance from a point on the chamber angle circulation line (35) to the center (20) of the Chamber angle circumference (35) or to another point on the axis of symmetry (37) of the circular area enclosed by the chamber angle circumference line (35) or to an opposite point on the chamber angle circumference (35) is determined and thus directly to the radius (r) or the equivalent size can be closed.

20. The method according to claim 18, characterized in that the distance from the opening (36) in the cornea (31) to the opposite chamber angle (35) is determined by contact measurement of the insertion body (12; 1 12; 212) with the chamber angle circulation (35) is and thus the diameter of the front chamber (30) can be estimated.

21. Method according to one of claims 18 to 20, characterized in that the side lengths of an isosceles triangle lying in or near said surface are determined, from which two corner points on the chamber angular circumference (35) and the third corner point lie on the center point (20) or another point on the axis of symmetry of the circular area enclosed by the chamber angle circumference line (35) and thus the leg length of the triangle corresponds to said radius (r).

22. The method according to any one of claims 18 to 21, characterized in that the measuring device (10; 1 10; 210) has an insertion body (12; 1 12; 212) which through the cornea (31) into the anterior chamber (30) is inserted and the anterior chamber (30) is pushed through in such a way that it is preferably on the one hand near or in the center (20) of the area enclosed by the ventricular angle circumference line (35) and on the other hand with the section of the ventricular angle opposite the corneal opening (36) (35) comes into contact at least at one point, the insertion body (12; 1 12; 212) comprising or being functionally coupled to a determination unit (14, 14a; 1 14, 1 19; 214), by means of which, depending on the maximum possible feed of the insertion body (12; 1 12; 212) the said radius (r) or the equivalent size can be determined.

23. The method according to any one of claims 18 to 22, characterized in that said radius (r) or the equivalent size through the cornea (31) from the determination unit (14, 14a; 1 14, 1 19; 214) is read ,

24. The method according to any one of claims 18 to 23, characterized in that the determination unit (14, 14a; 1 14, 1 19; 214) as a scale (14, 14a; 1 14, 1 19; 214) on the measuring device (10 ; 1 10; 210) and that light from outside the eye along the axis of symmetry (37) of the anterior chamber (30) intersecting the center point (20) of the chamber angular circumference (35) onto the scale (14; 1 14, 1 19, 214 ) is blasted and generates a readable signal there.

25. The method according to any one of claims 18 to 24, characterized in that the surface of the cornea (31) is scratched by a sharp tip with the aid of a guide which is positioned over the cornea (31) on the axis of symmetry (37) of the eye , and that light is directed along the axis of symmetry (37) of the eye to this marked point, so that the marking is shown on the scale graduation of the advanced measuring device (10; 110; 210).

26. The method according to any one of claims 18 to 25, characterized in that the position of the measuring device (10; 110; 210) in the anterior chamber (30) by irradiation of light from an illuminating device arranged opposite the cornea (31), for example one Ring light, is checked by observing the reflexes on the cornea (31) andZoder on the lens (34).

27. The method according to claim 18, characterized in that the insertion body of the device according to claims 13 to 16 is advanced such that the two openings (315b) are as close as possible in the area of said center (20), the sensor (316) and the base body (315) when the sensors are extended

(316) is pushed back and forth until the sensors (316) can be extended to the maximum.

28. The method according to any one of claims 18 to 27, characterized in that on the insertion body a light or sound transmitter and a Zoder

Light or sound receivers are arranged and that the radius (r) or an equivalent size are determined by means of optical or acoustic methods, for example reflection, absorption and time measurements.