DE10002672A1 - Device and method for determining the radius or the diameter of the chamber angle of an eye - Google Patents

Abstract

In order to select the correct size of a lens to be implanted in a front chamber of an eye in phakic eyes, a measuring device for determining the radius (r) or an equivalent size of the area enclosed by the chamber angular circumference line (35) of the front chamber (30) is assumed to be circular . 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), and a determination unit (14) on the insertion body (12), which is designed in this way is that the relative position of at least two points of the said surface, in particular its distance, can be determined, it being possible to infer the said radius (r) or the equivalent size from this relative position. A method for the said determination of the radius (r) or the equivalent size is also specified.

Description

The invention relates to a measuring device for determining the radius or an equivalent size to that of the anterior chamber angular orbit Chamber of an eye enclosed, essentially circular area.

The invention further relates to a method for determining the radius or an equivalent size to that of the anterior chamber angular orbit Chamber of the eye enclosed, essentially circular area.

In recent years, refractive surgery has mainly been carried out by Exci mer laser surgery dominates. While it quickly became clear that the PRK (photo refracive keratectomy) is unsuitable for high myopias the LASIK (laser in situ keratomileusis) the hope, hereby also highest My to be able to correct opies satisfactorily. Meanwhile, however, in this regard a certain disillusionment occurred. With myopia of more than 10 dpt. the spread of the refraction results is already increasing significantly. Come in addition, that in relation to the pupil size the treatment zones for the laser too are small, which is especially true at dusk and younger patients with a dilatable pupil can lead to problems. Another anatomical limitation results from the fact that when falling below a residual corneal thickness of 50 percent of the initial value the risk of Corneal ectasia (bulging due to mechanical instability) considerably increases.  

Against this background, this has been especially true for the higher myopias Interest in lens surgery has increased again in recent years. In addition to the long-known process of extracting the clear lens and their replacement with an intraocular lens, have also recently how of several authors on their experience in implanting intraoku Lar lenses in phakic (accommodation capable) eyes reported.

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

Thanks to improved lens materials and using modern auxiliaries tel, especially viscoelastics that protect the corneal endothelium in to stabilize the anterior chamber, however, it has been in recent years a certain renaissance of the implantation of intraocular lenses in phakic Eyes come. The success rate with which the target refraction is reached is currently somewhat worse than with the PRK and LASIK procedures. However, such statements must take into account that the phake Intraocular lens implantation is currently used by most surgeons Refractive errors are recommended where the accuracy of the other right Active surgical procedures are also relatively low.

The spectrum of indications for the lenses presented below is used by My opies from -7 to -20 dpt. and for hyperopia from +5 to +10 D seen. However, especially with the higher hyperopias, that in the front section of hyper-hyperopic eyes there are relatively narrow conditions . Especially in patients with already limited accommodation is therefore used in these cases by some operators of the extraction of the clear Priority was given to lenses and their replacement with conventional intraocular lenses.  Another indication for the implantation of intraocular lenses in pha ke eyes can be the correction of higher grade astigmatism. Stand for it Toric lenses have recently become available.

Very different intraocular lens models are currently used det, with both posterior chamber lenses, iris lenses and anterior chamber lenses Find use.

Posterior chamber lenses for implantation in phakic eyes are still relatively new. These are thin, soft intraocular lenses, which can be enlarged by the tter pupil in front of the natural lens in the sulcus ciliaris.

Worst iris claw lens, also for implantation in phakic eyes is suitable, it is a biconcave intraocu made of PMMA lar lens that uses a claw-shaped feel in the middle peripheral immobile Portion of the iris is fixed.

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, especially in the sense of progressive decompensation due to loss of endothelial cells on the inner side of the cornea, seem to have been eliminated in the newer anterior chamber models. They are foldable and can therefore also be implanted using small incision techniques, which can generally avoid the induction of surgical astigmatism.

The diameter of the anterior chamber in the area of the chamber angle is i. a. between 10 and 13 mm. The size of the implanted lenses, however, is typically 0.5-1 mm above to dislocate or rotate avoid. Currently the size of the lens used by the Vermes solution of the limbus diameter (transition from cornea to sclera) estimates. However, this estimate turned out to be relatively imprecise. Therefore, disadvantageously arises when using anterior chamberlin Often an irritation of the ventricular angle, which increases the drainage wi the level of the aqueous humor can result in the eye pressure increases (glaucoma). Various authors have also written about the so-called Ovalization of the pupil is reported by mismatched lenses knife can be caused. So are mechanical forces that the edge caused by too large lenses in the chamber angle for the ovalization of the Pupil responsible. The irritation states in the chamber angle are also shown in ers line caused by lenses that are too large and their contact pressure.

Alternative methods of measurement to estimate the geometric relationships of the Anterior chambers have so far not been found despite this deficiency.

It is an object of the present invention, an apparatus and a method of the type mentioned at the outset to provide a more precise estimate to achieve the geometric conditions in the anterior chamber so that it fits more accurate anterior chamber lenses can be inserted into the anterior chamber nen.

The object is thereby ge in the device of the type mentioned triggers that the device has an insertion body that passes through an opening in the Cornea is insertable into the anterior chamber, and a determination unit the insertion body, which is designed such that the relative position of at least two points of the aforementioned area, in particular its ab stood, is determinable, whereby from this relative position on the Ra dius or an equivalent size can be concluded.  

This is achieved in the process of the type mentioned at the outset solved that an opening is incised in the cornea, that a measuring device tion is introduced through the opening in the front chamber and that with the help the measuring device the relative position of at least two points of the said th area, in particular the distance, is determined such that from this relative location to said radius or an equivalent size ge can be closed.

The advantages of the invention can be seen in particular in the fact that by means of presented method or the device presented it intraoperatively a suitable measuring instrument is possible through the opening in the cornea, through which the lens should then preferably be introduced, into which To advance the anterior chamber. From the determination of the relative location of at least two points enclosed by the chamber angular orbit NEN area is then in a known manner - for example on the basis from simple geometric formulas or in the simplest case through direct ones Reading from a scale - to infer the radius of the anterior chamber. It it is assumed that the chamber angular circumference is an arc Are defined. Deviations from this circular arc shape are essentially ver negligible and are therefore not taken into account.

In the following, instead of "radius or an equivalent size" shortened the term "radius" used; with this term are accordingly also includes the equivalent sizes mentioned.

The at least two points mentioned can be determined, for example by means of optical and / or acoustic methods (reflection or absorpti measurements, transit time measurements) and / or mechanical methods be true. Such measurements make it much more accurate than in State of the art the radius (or diameter) of that of the ventricular angle line  to determine the enclosed area and based on this Values to choose the optimal anterior chamber lens for implantation.

The determination of the relative position of the points preferably consists of the Determination of their distance. For example, the determination is sufficient mung the distance of two points, z. B. the center of the Chamber angle circumference encircled circular area and a point on the Chamber angle circulation line (or - more simply - the chamber angle). Al The distance between two points at or near the chamber angle becomes alternative orbit measured, its direct connection by the means mentioned point runs and thus the diameter of the chamber angle Define the circular area described on the running line. For example, the Ab stood from the opening of the cornea to the opposite chamber angle section and - taking into account that the opening in of the cornea are above the angle of the chamber for operative reasons must conclude - who is the diameter of the chamber angle circulation lines the.

It should be noted that in the entire application under "Center" and "Point not necessarily the ideal location in the The center point or on the chamber angle orbit is to be understood; Points with small deviations from the center or from the chamber angle Lauflinie also fall under the aforementioned terms.

Alternatively or additionally, the side length of an isosceles, in the of the triangle enclosed by the chamber angle orbit determined, of which two corner points on the chamber angular orbit and the third corner point on said center point and thus the legs length of the triangle is equal to the radius sought. Through this three-point Measurement increases the measuring accuracy compared to that previously described Two-point measurement, consisting of the distance measurement of the center  the circular area enclosed by the chamber angle orbit to form a Point on the ventricular angle line.

The measuring device advantageously has a measuring rod Insertion body. This is preferably eccentrically through the cornea the anterior chamber is inserted and through the anterior chamber pushed that the insertion body in a feed position in the main Lichen above and preferably near the center of that of the Kammerwin circular circumscribed area and with which the corneal opening opposite chamber angle section at at least one point comes into contact. Via a determination unit on the introducer body can then the said radius according to the possible feed of the Insertion body can be determined, the determination unit being more advantageous example includes a reading or display unit.

Said radius can particularly preferably be that of the chamber angle line enclosed area or the said equivalent size by the Cornea can be read through from the determination unit if there is the insertion body in a feed position by touching the chamber angle located. For this purpose, a particularly advantageous embodiment Form of the invention provided that the determination unit as a scale on the Introducer body is formed and that a light beam from outside the front chamber along the axis of symmetry of the eye - which is the center of the eye intersects with the circular area bounded by the chamber angle circumference line - on the Scale is blasted and there generates a readable signal. Advantageously the light beam is reflected on the scale so that the value is the section of the scale where the light beam hits can be read directly can. For this it is sufficient that the scale has, for example, ten graduation marks, without necessarily having numbers or the like on the scale. The The operator of the measuring device can determine the position of the light beam close the radius on the scale. The individual tick marks can also  be different (e.g. be different lengths) by one realizing exact assignment.

Preferably, the scale is calibrated so that the radius of said one approximate circular area can be read directly and based on this value quickly selected the appropriate lens for implantation and after removing the Measuring device inserted through the opening in the cornea into the anterior chamber can be set. When calibrating, it can be taken into account that in the Measuring position the scale is not completely in the defi from the chamber angle orbit area - but mostly above - is arranged.

Instead of beaming a light beam directly onto the scale, one is advantageous Ten training provided, the cornea on the axis of symmetry to mark the intersecting point. For this purpose, for example, a metal tip on a guide above the cornea on the axis of symmetry or the op table axis of the eye and the cornea with this metal tip scratched. Then a ray of light along the axis of symmetry of the eye becomes cent ral directed at this marked point so that the marking on the Ska la and the radius can be read on the basis of this signal.

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

Alternatively or in addition, the measuring device has a scale which in ma ximal advanced state of the measuring device cuts the cornea, so that preferably at the intersection of the diameter or the radius - depending after calibration of the scale - can be read. When calibrating te are advantageously taken into account that the opening in the Cornea is not on the ventricular angle line, but is above it.  

The insertion body expediently takes on a shape which allows it to be inserted to be introduced into the front chamber in an elongated configuration. The Insertion bodies either inherently have such an elongated shape or can be in such can be brought, for example, by folding or otherwise Volume reduction.

The measuring device advantageously consists essentially of two of elongated bodies arranged at an angle to one another. One body becomes here from the insertion body and the other body from a handle body educated. In one measuring position, the grip body points away from the eye lens angled away from the insertion body and protruding from the corneal opening, while rend the insertion body and especially the scale preferably close above the center point of the one enclosed by the chamber angular orbit Area. By means of this configuration it is possible, on the basis of the Eye angled handle body on the one hand easy handling of the Realize measuring device and on the other hand relatively accurate measurements to carry out, since the insertion body and in particular the scale in the main Chen is arranged in the area defined by the chamber angle orbit. Otherwise, the trigonometric relationships must also be taken into account because the insertion body is then at a larger angle to that of the Chamber angle circumferential line would be advanced area.

In order to achieve the least traumatizing measurement possible, the Insertion body in a particularly advantageous embodiment, a flat distal end. The risk of injury to the sensitive endothelium This reduces the layer on the inner side of the cornea.

In an advantageous development of the invention, the insertion body is at least at least two parts. Form elongated in the feed direction th base body of the insertion body is pivoted, the essentially in the area defined by the chamber angle orbit  is pivotable so that the chamber angle on at least two of touched spaced points. For this purpose, the swivel arrangement For example, be substantially rod-shaped so that they are in ver swiveled position with the base body spanning a cross. The two free The ends of the swivel arrangement touch at different points cut the chamber angle.

The insertion body described above with the rod-shaped swivel arrangement voltage can be used to close said radius in two ways measure up. When folded, i. H. the swivel arrangement is aligned essentially with the base body, the free one pointing in the feed direction protrudes End of the swivel assembly beyond the free end of the base body and touches - in a first measuring position of the measuring device - in maximum Feed position the chamber angle. In this position the insertion body can by means of the aforementioned light beam from a first scale through the radius the cornea can be read.

For the second measurement, which is used, for example, as a control measurement, the Insertion body retracted, but remains in the anterior chamber. The Swivel arrangement can then - advantageously by means of leverage, d. H. Eccentrically offset force by means of pulling relative to the axis of rotation or push - swivel. For example, there is one free end of a rigid wire eccentrically connected to the swivel assembly. The The wire runs along the base body and through the opening in the Cornea out of the eye. By pulling or pushing on the from the The swivel arrangement can protrude into the free end of the wire their second measuring position pivoted and for pulling out the insertion body pers from the anterior chamber to its original insertion position be brought. If the swivel arrangement is swiveled into its measuring position, d. H. the swivel arrangement protrudes perpendicularly from the base body, the on guide body advanced again such that the free ends of the swivel touch the chamber angle. It is important to ensure that  the base body is above the center of that of the chamber angle circulation never defined circle.

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 insertion body is located above the center point of the ventricular angular line and the ka is librated that the radius can be read directly. The second measuring scale can with the measuring device advanced either in the area of the said ten center point or at the entrance of the measuring device in the front the chamber. The second scale can also be formed in two parts and is in both of the above positions.

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

In an alternative embodiment of the invention, the distal end of the insertion body on a loop that advanced in the anterior chamber bener position of the measuring device is extended and retractable and itself partially extends into a section of the chamber angle when extending. 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, the radius can be determined because the loop due to their material properties in a predetermined and reproducible Way in the chamber angle. The distal end of the insertion body is at a preferred embodiment designed as a tube. To the movement limit the loop when putting it into the chamber angle, the distal end of the insertion body can be two at a defined angle have fold-out legs so that the loop extends to the maximum driven, d. H. advanced state on the one hand to the unfolded Leg of the insertion body and the other on the two legs the opposite chamber angle section creates. This will make for  the insertion body defines a maximum feed position from which the Have the radius (r) or an equivalent size determined, for example using the scale intersecting said axis of symmetry in the feed position. Due to the multi-point contact of the loop with the chamber angle, one high measurement accuracy can be achieved.

For an exact determination of the radius, the correct position of the insertion body is required pers essential in the anterior chamber. With the above be Written embodiments of the invention must, for example, the one guide body or the base body the axis of symmetry of the anterior chamber (same cut the axis of symmetry of the cornea and the eye). Around Controlling the position is advantageously light by means of one of the corneas opposite lighting device blasted onto the cornea based on the light reflections on the cornea and on the lens on the position of the Close insertion body in the anterior chamber. This is advantageous Ring light used that is essentially symmetrical with respect to the horn skin is arranged. The insertion body can thus be in the fore be centered so that it crosses the axis of symmetry of the anterior chamber. A centrally illuminating light source can also be used, the one punctiform reflex generated. As an alternative to this - as already described above ben - a mark applied in the center of the cornea, light along the Radiated symmetry and the insertion body in the foreground mer positioned that the mark on the insertion body or on the Scale is mapped.

Further advantageous developments of the invention are due to the features of the subclaims.

In the following three embodiments of the invention are explained in more detail tert. Show it:

FIG. 1 shows a known anterior chamber lens;

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

Fig. 3 is a plan view of the measuring device according to the Fig. 2;

Fig. 4: a plan view of a second embodiment of the inven tion with a swivel arm in the folded state in the maximum advanced position;

Fig. 5 is a plan view of the measuring apparatus according to Figure 4 in the pivoted state;. and

Fig. 6: a plan view of a third embodiment of the invention with an extendable loop in the maximum advanced position.

In Fig. 1 a known anterior chamber lens 1 named "NuVita" Bausch & Lomb is shown. A lens body 2 is provided centrally, which has two curved arms 4 on two opposite edge regions, which are supported on the sections 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 bordered on 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 32 with a central pupil 33 and the lens 34 arranged underneath. The circumferential section in which the cornea 31 and the iris 32 collide is the chamber angle 35 (hereinafter also referred to as the cam angle circumferential line 35 ).

The measuring device 10 according to FIG. 2 (shown in the advanced position 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 free end 13 of the insertion body 12 - at the same time the distal end of the measuring device 10 - runs narrow and flat. This end is preferably rounded off in such a way that the radius of curvature is smaller than the radius of the substantially circular chamber angle orbit. The insertion body has a scale 14 , which is divided, for example, at half-millimeter intervals and is clearly visible from the outside of the eye with appropriate lighting. Additionally or alternatively, a scale 14 a arranged at the proximal end of the measuring device can be provided.

To use the measuring device 10 shown in FIG. 2, an opening is eccentrically cut into the cornea 31 and the insertion body 12 - while holding the handle body 11 - through the opening 36 created in the cornea 31 into the front chamber 30 and until its narrow contact dista len end 13 advanced with the opening 36 opposite the chamber angle 35 without touching the endothelial layer on the inside of the cornea 31 if possible. The handle body 11 still protrudes from the opening 36 . In this position, the scale 14 is as close as possible to the center 20 of the area written by the chamber angular circumference 35 , the radius r or diameter of which is ultimately to be determined. The total width of the scale 14 is selected such that both unusually small and large anterior chamber radii r can be determined. The scale 14 a is shown in FIG. 2 in the advanced state of the measuring device in the region of the opening 36 of the cornea and is calibrated taking into account the angular relationships (because of the position of the opening 36 above the chamber angular circumference line 35 ) such that this too Scale 14 a the radius or the diameter can be read.

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 line 35 , can be achieved in that light from one of the corneas 31 opposite illumination device (not shown) is radiated onto the eye, for example by a ring light. The position of the insertion body 12 in the anterior chamber 30 can then be checked by observing the flexe on the cornea 31 and / or on the lens 34 . In addition, a centrally illuminating light source can be used, which generates a point-like reflex.

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 line 35 . This water light beam is reflected on the scale 14 , the point of impact on the scale 14 can be observed through the cornea 31 . In this way, an extremely easy yet precise reading of the radius r is possible.

Alternatively, the cornea 31 is incised at its point of 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 section aligned with this hole is marked - for example by tiny incisions. 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 in one direction become smaller and smaller 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 , an experienced operator can deduce the radius r from the reflected signal.

In the second embodiment of the invention according to FIGS . 4 and 5, the measuring device 110 again consists of a handle body 11 (not shown in the top view of FIGS . 4 and 5) and an insertion body 112 , which in this case is formed in two parts. The insertion body 112 has a base body 115 and an articulated to its distal end Schwenkan arrangement 116 , which is rod-shaped in the illustrated embodiment and is pivotable substantially 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 119 . The length of the rod-shaped Schwenkanord voltage 116 is chosen such that it does not cover the first scale 114 in the aligned state with the base body by 115 .

The measuring device 110 according to the second embodiment is brought for insertion into the front chamber 30 through the opening 36 into a position in which the base body 115 and the pivot arrangement 116 are aligned. For a first measurement, the measuring device 110 is then advanced against the chamber angle 35 opposite the opening 36 , it being necessary to ensure that the base body 115 intersects the axis of symmetry 37 of the anterior chamber (which coincides with the optical axis of the eye) and the first scale 114 is therefore above the center 20 of the Kammerwinkelum running line ( Fig. 4). 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 an independent measurement by means of the measuring device 110 according to FIGS . 4 and 5 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 which is articulated with respect to the swivel axis 117 (not shown), which engages the pivot arrangement 116 and is guided out of the front chamber 30 through the opening 36 along the measuring device 110 . In Fig. 5 it is shown that the pivot assembly is pivoted 116 relative to the Ba siskörper 115 by 90 ° and then a maximum again advanced against the anterior chamber angle 35, so that the free ends 118 of the pivot assembly 116 abut the chamber angle 35. In this case, the second scale 119 now 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 ultimately the side lengths of an isosceles triangle are determined, from which two corner points on the chamber angle circumference line 35 and the third corner point lie on the center point 20 of the chamber angle circumference line 35 and thus the leg length of the triangle corresponds to said radius r corresponds. The second scale 119 can accordingly be calibrated according to simple and known geometric formulas.

To pull out the measuring device according to FIGS . 4 and 5, the swivel arrangement 116 is brought back into position with the base body 115 .

In FIG. 6, a third embodiment of the invention is shown. The operation is in principle similar to that of the embodiment according to FIGS . 4 and 5. In the measuring device according to FIG. 6, the distal end of the insertion body 212 in the longitudinal direction in two legs 212 a can be folded out, for example, only by means of a stop Fold out up to a maximum angle α. The insertion body 212 is formed from a hollow shape. In its interior a loop 216 is arranged, which z. B. can be extended or retracted by pressure or train. If the insertion body 212 has been inserted into the front chamber 30 in the folded state of the legs 212 a, the loop 216 is extended, whereby the legs 212 a spread apart. In the maximally extended state of the loop 212 a, this lies on the one hand on the inner sides of the legs 212 a and on the other hand - with corresponding advancement of the insertion body 212 - at the opening 36 opposite the chamber angle section GE. The material of the loop 216 is chosen such that it can never penetrate 35 into the relatively narrow space between the free ends of the legs 212 a and the Kammerwinkelumlaufli. From the maximum feed position of the Einführkör pers 212 can be determined on the scale 14 in the manner described above, the radius r. When the loop 216 is retracted, the legs 212 a fold - again, for example, caused by a spring acting between them accordingly - again; alternatively, the legs 212 a are pressed together when the loop 216 is driven when the insertion body 212 is pulled out of the front chamber 30 through the narrow point of the opening 36 .

Based on the above measurements, a more precise selection of an in the front chamber to be fitted lens.

Claims (19)

1. Measuring device for determining the radius (r) or an equivalent size of the substantially circular surface enclosed by the chamber angular circumference ( 35 ) of the anterior chamber ( 30 ) of an eye, comprising an insertion body ( 12 ; 112 ; 212 ) which passes through an opening ( 36 ) in the cornea ( 31 ) in the anterior chamber ( 30 ) is insertable, and a determination unit ( 14 , 14 a; 114 , 119 ) on the insertion body ( 12 ; 112 ; 212 ), which is designed such that the relative The position of at least two points of said surface, in particular its distance, can be determined, it being possible to infer said radius (r) or an equivalent size from this relative position. 2. Device according to claim 1, characterized in that the insertion body ( 12 ; 112 ; 212 ) is designed such that it has an elongated shape when inserted into the front chamber ( 30 ) or when it is pulled out of the front chamber ( 30 ) or into a such can be brought. 3. Device according to one of the preceding claims, characterized in that the measuring device ( 12 ; 112 ; 212 ) is essentially formed by two elongated bodies arranged at an angle from one another, one body being formed by a handle body ( 11 ) and the other body being formed by the Insertion body ( 12 ; 112 ; 212 ) is formed and the insertion body ( 12 ; 112 ; 212 ) is in a measuring position close to the center point ( 20 ) of the circular area enclosed by the circumferential angle of the chamber angle, while the grip body ( 11 ) is located by the eye lens ( 34 ) is angled away from the insertion body ( 12 ; 112 ; 212 ) and protrudes from the cornea opening ( 36 ). 4. Device according to one of the preceding claims, characterized in that the determination unit ( 14 , 14 a; 114 , 119 ) on the insertion body ( 12 ; 112 ; 212 ) arranged first scale ( 14 , 14 a; 114 ), which is located in the area of the opening ( 36 ) of the cornea ( 31 ) or above the center point ( 20 ) of the circular area delimited by the chamber angle circumference line ( 35 ) when the insertion body ( 12 ; 112 ; 212 ) is at a maximum against the chamber angle ( 35 ) advanced measuring position. 5. Device according to one of the preceding claims, characterized in that the insertion body ( 12 ; 112 ; 212 ) has a flat distal end in order to enable the least possible traumatizing contact with the chamber angle ( 35 ). 6. Device according to one of the preceding claims, characterized in that the insertion body ( 112 ) has a base body ( 115 ) and a pivoted to the base body ( 115 ) pivot arrangement ( 116 ) which in the area defined by the chamber angular circumference line ( 35 ) can be pivoted so that it touches the chamber angle ( 35 ) at least at two spaced apart points. 7. The device according to claim 6, 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 ( 118 ) of the pivot arrangement ( 116 ) touch the chamber angle ( 35 ). 8. The device according to claim 6 or 7, characterized in that the insertion body ( 112 ) has a second scale ( 119 ) which is in the second measuring position of the measuring device ( 110 ) in the region of the opening ( 36 ) of the cornea ( 31 ) or intersects the center point ( 20 ) of the chamber angle orbit ( 35 ) and from which the said radius (r) or the equivalent size can be read. 9. Device according to one of the preceding claims, characterized in that the pivoting arrangement ( 116 ) by means of pulling or pushing is eccentrically offset from the pivot axis ( 117 ) offset force action. 10. Device according to one of claims 1 to 5, 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 line ( 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. 11. Device according to one of the preceding claims, characterized in that the first and / or second scale ( 14 , 14 a; 114 , 119 ) is calibrated such that the radius (r) of said surface can be read directly. 12. A method for determining the radius (r) or an equivalent size of the substantially angular surface enclosed by the chamber angular circumference ( 35 ) of the front chamber ( 30 ) of an eye, in particular by means of the measuring device according to claims 1 to 11, characterized in that an opening ( 36 ) is cut into the cornea ( 31 ), that a measuring device ( 10 ; 110 ; 210 ) is inserted through the opening ( 36 ) into the anterior chamber ( 30 ) and that with the aid of the measuring device ( 10 ; 110 ; 210 ) the relative position of at least two points of the said surface, in particular the distance, is determined such that the said radius (r) or the equivalent size can be inferred from this relative position. 13. The method according to claim 12, characterized in that in a first measuring position of the measuring device ( 10 ; 110 ), the distance from the center ( 20 ) of the chamber angle circulation line ( 35 ) to a point on the chamber angle circulation line ( 35 ) is determined and thus directly on the Radius (r) or the equivalent size can be closed or the distance from the opening ( 36 ) in the cornea ( 31 ) to the opposite chamber angle ( 35 ) is determined and thus the diameter of the anterior chamber ( 30 ) can be estimated. 14. The method according to claim 12 or 13, characterized in that in a second measuring position of the measuring device ( 110 ) the side lengths of an isosceles triangle lying in said surface are determined, from the two corner points on the chamber angular contour line ( 35 ) and the third corner point lie on the center point ( 20 ) 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). 15. The method according to any one of claims 12 to 14, characterized in that the measuring device ( 10 ; 110 ) has an insertion body ( 12 ; 112 ; 212 ) which is inserted through the cornea ( 31 ) into the anterior chamber ( 30 ) and the anterior chamber ( 30 ) is pushed through in such a way that on the one hand it is preferably close to the center ( 20 ) of the surface enclosed by the ventricular angle circumference line ( 35 ) and on the other hand at least at one point with the section of the ventricle angle ( 35 ) opposite the cornea opening ( 36 ) comes into contact, the insertion body ( 12 ; 112 ; 212 ) comprising a determination unit ( 14 , 14 a; 114 , 119 ), by means of which, depending on the maximum possible advance of the insertion body ( 12 ; 112 ; 212 ), said radius (r) or the equivalent size can be determined. 16. The method according to any one of claims 12 to 15, characterized in that said radius (r) or the equivalent size through the cornea ( 31 ) from the determination unit ( 14 ; 114 , 119 ) is read. 17. The method according to any one of claims 12 to 16, characterized in that the determination unit ( 14 ; 114 , 119 ) is designed as a scale ( 14 ; 114 , 119 ) on the measuring device ( 10 ; 110 ) and that a light beam from outside the Eye along the axis of symmetry ( 37 ) of the anterior chamber ( 30 ) intersecting the center point ( 20 ) of the ventricular angle circumference line ( 35 ) onto the scale ( 14 ; 114 , 119 ) and generating a readable signal there. 18. The method according to any one of claims 12 to 17, characterized in that the surface of the cornea is scratched by a metallic tip with the aid of a guide which is positioned over the cornea on the axis of symmetry ( 37 ) of the eye, and that light along the Axis of symmetry ( 37 ) of the eye is directed at this marked point so that the marking is shown on the scale graduation of the advanced measuring device. 19. The method according to any one of claims 12 to 18, characterized in that the position of the measuring device ( 10 ; 110 ; 210 ) in the front chamber ( 30 ) by irradiating light from one of the cornea ( 31 ) opposite lighting device, for example a ring light, is controlled by observing the reflexes on the cornea ( 31 ) and / or on the lens ( 34 ).