RU2812387C1 - Method of fixing toric intraocular lens to iris - Google Patents

Abstract

FIELD: medicine, ophthalmology.

SUBSTANCE: invention can be used for fixing a toric intraocular lens (TIOL) to the iris. The axis of the TIOL cylinder corresponding to the axis of the suture fixation of the lens is determined before surgery. Two control marks of the axis position are applied to the dial. Corneal paracenteses are formed in the projection of the marks of the axis of suture fixation of the lens. Through both paracentesis, two iris retractors are passed towards each other. Each retractor is fixed externally by the cornea in the area of one paracentesis with a hook at its end, and in the opposite paracentesis with a retractor sleeve. The fixing suture is placed on a circle passing 3.0 mm from the pupillary edge of the iris with a pupil diameter of 2.5 mm. The distance between the injection and the puncture is divided into two equal parts by iris retractors within an interval of 1.4–1.8 mm, for which the cornea, then the iris, and the anterior capsule of the lens are pierced with a needle. The needle and thread are passed under the haptic part of the TIOL and withdrawn transcorneally or into paracentesis, meeting the needle with a conductor. Then a slip knot is formed so that the loop passes over the iris retractors and tightened.

EFFECT: invention makes it possible to simplify the manipulation of suturing, reduce trauma to eye tissue and reduce the risk of postoperative complications, due to controlled tightening of the thread when forming a loop, strict positioning of the axis of suture fixation of TIOL, and the use of one thread to fix each supporting element of TIOL to the iris.

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Description

The invention relates to medicine, namely to ophthalmic surgery, and can be used for fixing a toric intraocular lens to the iris during phacoemulsification of complicated cataracts, as well as for repositioning a previously implanted intraocular lens.

In standard situations, implantation of an intraocular lens (IOL) is performed in the capsular bag of the lens, where the lens is fixed and centered due to the design features of the fastening (haptic) elements. The need for additional fixation of the IOL arises in the absence of a capsular bag (a consequence of previous operations or injuries), its damage, weakness and failure of the ligamentous apparatus of the lens, as well as in the case of dislocation of a previously implanted intraocular lens.

In cases of severe corneal astigmatism, to achieve maximum functional results, there is a need to implant toric IOLs. However, this type of IOL requires precise positioning, which is technically extremely difficult in the absence or failure of the capsular bag. Rotation of the toric IOL relative to the calculated location, decentration and tilt significantly worsen the final functional result.

Toric intraocular lenses (TIOLs) began to be used in the 90s of the last century for the simultaneous correction of corneal astigmatism during cataract surgery. A feature of toric lens implantation is the preoperative determination of the strong axis of corneal astigmatism by performing, for example, keratotopography to obtain a keratotopogram and applying control landmarks to the limbus using special markers or notches. During implantation, the toric lens is inserted into the capsular bag and the axis of the IOL cylinder is set along the strong meridian of the cornea according to the control marks on the limbus (Tsinopoulos I.T., et al. Acrylic toric intraocular lens implantation: a single experience concerning clinical outcomes and postoperative rotation // Clinical Ophthalmology 2010: 137-142).

In clinical practice, for a number of reasons, subluxation or dislocation of the toric lens-capsular bag complex can often be observed. There are a number of surgical methods for repositioning the dislocated IOL-capsular bag complex, accompanied by its suture fixation to the sclera or iris. However, such disadvantages of scleral suturing of the complex as frontal displacement of the IOL, the technical complexity of the operation, the likelihood of vitreous prolapse, retinal detachment, and intraocular hemorrhage are obvious.

There is a known method of scleral fixation of a toric posterior chamber IOL (TIOL) in case of failure of the ligamentous apparatus of the lens or the absence of a capsular bag. Before implantation of TIOL, the strong and weak meridians of the cornea are marked. In this case, along the axis of the strong meridian, 2 mm from the limbus, the point of future fixation of TIOL to the sclera is marked. Then the conjunctiva is separated in areas perpendicular to the TIOL axis. In this case, before implantation, TIOL is stitched at the root of the haptic or through the haptic with two threads of Prolene 8.0, the free ends of the threads are coagulated until thickenings are formed, the first needle is passed through the injector, inserted into the anterior chamber, passed under the iris and punctured at the calculated point on the sclera using a needle. conductor. TIOL is placed in a cartridge and implanted into the posterior chamber of the eye. The second needle is inserted through the main access into the anterior chamber retrogradely with the thread forward, intercepted with tweezers through paracentesis and placed at the calculated point of the sclera, also using a guide needle, the TIOL is oriented along the axis by tensioning the thread. After centering TIOL relative to the center of the cornea, the ends of the threads brought to the surface of the sclera are coagulated until thickenings form and are immersed in the sclera under the conjunctiva. Then a U-shaped suture is formed with a 10/0 nylon thread, while the conjunctiva is first separated and markings are made: 2.5 mm from the limbus and 2.5 mm from the axis of the weak meridian, the entry points of the thread into the sclera are marked. After which the needle and thread are passed through the marked point under the TIOL perpendicular to its axis and brought out on the opposite side of the sclera using a guide needle, a thickening is formed at the free end of the thread. Then the needle is brought out in the same way to the opposite side of the sclera, the threads are pulled, the needle is cut, a thickening is also formed at the second end of the thread, and the conjunctiva is sutured (patent RU2785485 C2, published 12/08/2022).

The disadvantages of this method are: frequent tilting of TIOL, the need for a coagulator, additional manipulations with the conjunctiva, the danger of cutting through the coagulated ends of the thread through the conjunctiva.

There is a known method of fixing TIOL during its luxation into the vitreous body, which consists in the following. After moving the intraocular lens from the vitreous cavity into the anterior chamber of the eye onto the iris and placing the lens on each side of the lens at the same distance from the pupillary edge, symmetrically relative to the supporting element of the lens, laser iridotomies are performed. Through each pair of iridotomies, a needle and thread are passed to fix each haptic element of the lens, bringing the ends of the threads out onto the cornea through paracenteses made in the areas of lens fixation, and forming a stitch under the iris on each side of the lens. Each stitch is grabbed one by one under the iris, brought into the anterior chamber of the eye, a lens is placed on each haptic element and moved under the iris. In the case of luxation of TIOL into the vitreous, when it is moved from the vitreous cavity to the anterior chamber of the eye to place an intraocular lens, when centering TIOL, its axial marks are oriented according to the markings previously applied to the cornea (patent RU 2619748 C1, published 05/17/2017).

The disadvantages of this method are: the need for an endolaser, repositioning of TIOL is performed during mydriasis, which can lead to an abnormal shape of the pupil after constriction, and multiple manipulations of TIOL in the anterior chamber increase the risk of corneal edema, endothelial damage and hemorrhagic complications.

The prototype closest to the claimed method is the method of suture fixation of the “toric lens-capsular bag” complex to the iris in case of subluxation of the complex, which consists of the following. Reposition of TIOL and fixation of each supporting element to the iris is performed using two threads; for this, the first thread is first passed through the cornea and iris from the side of one control landmark on the limbus, and the injection and puncture into the iris are performed in such a way that the strong axis of corneal astigmatism passes between injected and punctured, and the stitch on the iris was located 2.5-3 mm from the edge of the pupil with a length of 1-2 mm. Then the thread is passed through the cornea and iris in the same way from the side of the second control landmark on the limbus. After this, through the cornea in the area of the base of one of the supporting elements, a second thread is passed on a needle into the posterior chamber, which is used to go around the base of the supporting element and poke out. Then, in the same zone, from under the iris with a hook into the pupil zone, the first thread is pulled in the form of a loop, and one end of the second thread is inserted into this loop and the ends of the second thread are tied into a knot, fixing the supporting element to the first thread. The same steps are repeated on the opposite side of the lens. After this, they return to the two ends of the first thread drawn through the iris from one control landmark and the other: the ends of each thread are brought out into the first and second paracenteses, then the threads are pulled, centering the lens, and interrupted sutures are tied (patent RU 2720527 C1, publ. 30.04. 2020).

The disadvantages of this method are:

- repositioning of the toric lens and fixation of each supporting element to the iris is performed using two threads;

- lack of control of thread tension when forming a loop, which can lead to deformation, ovalization of the pupil, and disruption of the diaphragmatic function of the iris;

- difficulty in carrying out the method as a preventive fixation of TIOL;

- the method cannot be used in the presence of pronounced changes in the iris (colobomas, partial aniridia, iridocorneal fusion, iridodialysis);

- there is a danger of discrepancy between the final refraction and the calculated one, because when sutured to the iris, TIOL moves anteriorly;

- with severe incompetence or absence of the capsular bag, there is a risk of developing various complications (UGG syndrome, macular edema, development of transillumination zones, etc.) due to prolonged contact of the posterior surface of the iris and TIOL.

The objective of the invention is to develop a simpler and less traumatic method for preventive fixation of TIOL to the iris during phacoemulsification of complicated cataracts, as well as fixation during reposition of a previously implanted intraocular lens.

Technical result: simplifying the method, reducing its trauma and reducing the risk of postoperative complications.

The proposed method is as follows.

The first stage, under the control of a slit lamp under drip anesthesia, marks the horizontal axis of the patient’s eye 0-180°. Then, under an operating microscope using a marker, the axis of the TIOL cylinder is marked on the limbus, which corresponds to the axis of the suture fixation of the IOL, which was determined by the authors of the present invention by mathematical modeling for a monolithic IOL with an S-shaped haptic with a total size of 13 mm and a diameter of the optical part of 6.0 mm at provided that the seams will be located at a distance of 3.0 mm from the pupillary edge of the iris with a pupil diameter of 2.5 mm (Fig. 1), that is, on a circle with a diameter of 8.5 mm relative to the center of the pupil. Next, one corneal paracentesis with a width of 1.2 mm is carried out in the projection of the TIOL suture fixation axis marks. Paracenteses are performed at the level of the limbus in a plane parallel to the iris. After medicinal narrowing of the pupil using the drug “carbachol” to 2.5-3.0 mm and filling the anterior chamber with viscoelastic, TIOL is positioned in the plane of the iris and centered in the center of the pupil. Then, through both paracenteses, two iris retractors are passed towards each other so that the retractor is fixed externally by the cornea in the area of one paracentesis with a hook at its end, and in the opposite paracentesis - with a retractor sleeve (Fig. 2). The stitch of the fixing suture is placed on a circle passing 3.0 mm from the pupillary edge of the iris with a pupil diameter of 2.5 mm, which corresponds to the maximum safe anatomical zone. The injection/puncture distance (Fig. 3) is divided into two equal parts by iris retractors within an interval of 1.4-1.8 mm for correct positioning of TIOL and preventing pupil deformation in the postoperative period. Use a 13 mm needle with 1/4 curvature and 10-0 polypropylene thread. The cornea is pierced with a needle, then the iris in the area described above, observing the parameters of the puncture/puncture distance, then the anterior capsule of the lens, then the needle and thread are passed under the haptic part of the TIOL and removed transcorneally, or into paracentesis, meeting the needle with a conductor. Next, a sliding knot is formed so that the loop passes over the iris retractors and tightened. Similar actions are carried out with the opposite haptic element. The iris retractors are then removed by removing the sleeve and pulling out by the hooks. The viscoelastic is washed out from the anterior chamber, the paracenteses are hydrated with a balanced salt solution, and at the end of the operation, 0.1 ml of antibiotic is injected into the anterior chamber.

In the proposed method, installed iris retractors play the role of a thread tension limiter when tightening the knot and help to accurately position the fixing sutures and, accordingly, TIOL, which makes it possible to standardize the process of fixing TIOL to the iris. The suture loops obtained in this way will reliably fix the TIOL in the desired position, while maintaining the “iris-TIOL” space and without over-tightening the seams, which eliminates the deformation of the pupil and does not disrupt the diaphragmatic function of the iris.

The method is illustrated by drawings showing a diagram of the method.

In fig. Figure 1 shows the axis of the TIOL cylinder, corresponding to the axis of suture fixation of TIOL; the dotted line indicates the optimal distance for suture fixation of TIOL at 3.0 mm from the edge of the pupil with a pupil diameter of 2.5 mm, that is, a circle with a diameter of 8.5 mm relative to the center of the pupil.

In fig. Figure 2 shows a diagram of the passage of two iris retractors through the paracentesis, with each retractor fixed externally by the cornea in the area of one paracentesis with a hook at its end, and in the opposite paracentesis with a retractor sleeve.

In fig. Figure 3 shows a mathematical modeling diagram for calculating the optimal tension of the suture thread, where the iris is in the form of a shaded rectangle with a thickness of 0.5 mm; TIOL haptic in the form of a square with a side of 0.49 mm; 0.98 mm segment equal to two TIOL haptics and reflecting the variety of TIOL haptic widths depending on the lens model; 0.25 mm distance from iris to TIOL; a segment of 1.1 mm corresponds to two iris retractors occupying the entire width of the paracentesis; the dotted line corresponds to the middle of the injection/puncture segment; the injection/puncture distance itself is variable due to the difficulty of precise control and is divided by iris retractors into two equal parts within the range of 1.4-1.8 mm.

The inventive method makes it possible to simplify the manipulation of suturing, reduce trauma to eye tissue and reduce the risk of postoperative complications.

The advantages of the proposed method in comparison with the prototype are:

1. The ability to control the tightening of the thread when forming a loop.

2. Strict positioning of the axis of suture fixation of TIOL.

3. Using one thread to fix each TIOL support element to the iris.

An information search in scientific, technical and patent sources showed that in the available literature there is no information about a similar method, which allows us to conclude that the proposed method meets the criteria of the invention “novelty and inventive step”.

The invention is illustrated by the following examples of specific implementation.

Example 1

Patient K., 77 years old, applied to the Eye Microsurgery Center with complaints of low vision in the left eye (OS). Upon examination, a diagnosis was made: Complicated cataract of the left eye, pseudoexfoliation syndrome (PES), degree II lens subluxation.

During the examination, Vis OS=0.001 nc.

Keratometry: OS K1 41.31 ax 21°; K2 46.48 х 111°, DK-5.17 х 21°.

Objectively: OS is calm. The cornea is transparent, the anterior chamber is of medium depth, the moisture is transparent, the pupil is round, 3.0 mm in diameter, diffuse opacification of the lens. The fundus of the eye is not ophthalmoscoped.

Phacoemulsification of cataract (FEC) was performed with fixation of TIOL (Alcon SN6AT8) to the iris using the claimed method.

The first stage, under the control of a slit lamp under drip anesthesia, marked the horizontal axis of the patient's eye 0-180°. Then the axis of suture fixation of TIOL was calculated, which was 111° and marked using a marker on the limbus. Next, corneal paracenteses 1.2 mm wide were made in the projection of the suture fixation axis marks at the level of the limbus in a plane parallel to the iris. After drug-induced miosis of the iris with the drug “carbachol” and filling the anterior chamber with viscoelastic, TIOL was positioned in the plane of the iris and centered in the center of the pupil. Then, through both paracenteses, two iris retractors are passed towards each other so that the retractor is fixed externally by the cornea in the area of one paracentesis with a hook at its end, and in the opposite paracentesis - with a retractor sleeve. The stitch of the fixing suture is placed on a circle passing 3.0 mm from the pupillary edge of the iris with a pupil diameter of 2.5 mm. The distance of injection into the iris was divided into two equal parts by iris retractors, and it was 1.8 mm. Using a 13 mm 1/4 needle with a 10-0 polypropylene thread, the cornea was pierced, then the iris, observing the parameters of the injection/puncture distance, then the anterior capsule of the lens, then the needle and thread were passed under the haptic part of TIOL and brought into paracentesis at 9 o’clock, meeting needle as a guide. Next, a slip knot was formed so that the loop passed over the iris retractors and tightened. Similar actions were carried out with the opposite haptic element. Then the iris retractors were removed, the coupling was removed and pulled out by the hooks. The viscoelastic was washed out from the anterior chamber, the paracenteses were hydrated with a balanced salt solution, and at the end of the operation, 0.1 ml of antibiotic was injected into the anterior chamber.

The next day Vis OS: 0.16 sph. -2.50 cyl. -0.5 ax 60°=0.45, the cornea is transparent, the chamber is 3.0 mm, the aqueous humor of the anterior chamber is transparent, the pupil is 3.0 mm of regular round shape in the center, the sutures are adapted, TIOL in the center. There are atrophic foci in the macular area. The patient has been discharged.

Example 2

Patient M., 81 years old, applied to the Eye Microsurgery Center with complaints of low vision in the right eye (OD). From the anamnesis, 6 years ago, phacoemulsification of cataract with implantation of a toric intraocular lens J+J ZCT4.

During examination Vis OD=0.05 sph+9.0 cyl -1.50 ax 90=0.4.

Keratometry: OD OD K1 44.00 ax 172°; K2 45.71 x 82°, ΔK - 1.71 x 172°.

Objectively: OD is calm. The cornea is transparent, the anterior chamber is 3.5 mm, the aqueous is transparent, the pupil is 3.0 mm in the center. The TIOL-capsular bag complex is shifted to 5 o'clock, the edge of the optic, the haptic part, is visualized in the pupil area. There are multiple confluent drusen in the macula.

According to the IOL specialist, the recommended axis of TIOL position is 80°.

The TIOL was repositioned and sutured to the iris according to the claimed method, similar to Example 1, except that the axis of TIOL position was calculated to be 80°, the distance between the injection and puncture was 1.4 mm, and the needle was removed transcorneal.

The next day Vis OD: 0.4 sph -0.5=0.5, the cornea is transparent, the chamber is 3.5 mm, the aqueous humor of the anterior chamber is transparent, the pupil is 3.0 mm of regular round shape in the center, the sutures are adapted, TIOL in the center . The patient has been discharged.

The proposed method is characterized by its low-invasiveness, the absence of manipulations on the sclera and conjunctiva to cover the fixing sutures and nodes, as well as ease of implementation and cost-effectiveness.

Claims (2)

1. A method for fixing a toric intraocular lens to the iris, including preoperative determination of the cylinder axis of a toric intraocular lens (TIOL), corresponding to the axis of the suture fixation of the lens, with the application of two control marks of the axis position on the limbus, the formation of corneal paracenteses in the projection of the marks of the axis of suture fixation of the lens, reposition toric lens, and subsequent suture fixation of the supporting elements of the lens to the iris, characterized in that two iris retractors are passed through both paracentesis towards each other, and each retractor is fixed externally by the cornea in the area of one paracentesis with a hook at its end, and in the opposite paracentesis - retractor coupling, the fixing suture is placed on a circle passing 3.0 mm from the pupillary edge of the iris with a pupil diameter of 2.5 mm, the distance between the injection and puncture is divided into two equal parts by iris retractors within the range of 1.4-1.8 mm, for which they pierce the cornea with a needle, then the iris, the anterior capsule of the lens, pass the needle with a thread under the haptic part of TIOL and withdraw transcorneal or into paracentesis, meeting the needle with a conductor, then form a sliding knot so that the loop passes over the iris retractors, and tighten . 2. The method according to claim 1, characterized in that a 13 mm needle with a 1/4 curvature with a 10-0 polypropylene thread is used.