RU2375998C1 - Method of laser fragmentation of crystalline lens nucleus - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, namely to ophthalmic surgery. Tunnel access and corneal paracentesis are formed. WISKO-elastic is introduced, capsulorexis is carried out and crystalline lens nucleus is destroyed by laser energy of Nd-YAG laser with wavelength 1.44 mcm. Laser impact on nucleus is initially realised on capsulorexis border with formation of central fragment. After that fragment is raised with further laser impact parallel to natural way of crystalline lens fibres from the side of less strong nucleus substance and aspiration of destruction products.

EFFECT: method allows carrying out operation with small diametres of capsulorexis, as well as minimising laser influence on eye tissues to level of 130-170 mJ.

3 cl, 3 ex

Description

The invention relates to ophthalmology and can be used in the surgical treatment of cataracts.

A known method of laser extraction of cataracts with laser fragmentation of the lens nucleus (V. G. Kopaev, Yu.V. Andreev, A. Belikov, O. V. Kravchuk, A. Yu. Menshikov. Laser extraction of brown cataracts with Nd-YAG 1 , 44 μm laser // Bulletin of Ophthalmology, 2002, No. 1, p.23), which consists in acting on the nucleus from its center to the periphery, from the densest to the less dense layers of the lens. In this case, laser action on the central, most durable layers of the nucleus is carried out directly from its surface almost at right angles to the course of the lens fibers.

However, when laser cataract extraction is performed by this method, high energy levels are required to destroy the central part of the lens nucleus, and for complete fragmentation of the periphery of the large nucleus, “additional technical steps” are necessary even when capsulorhexis is larger than the diameter of the optics of the implanted intraocular lens.

An object of the invention is to develop a method for laser fragmentation of the lens nucleus with minimizing the levels of energy exposure to it and the surrounding eye tissue.

The specified technical result is achieved by the fact that in the method of laser fragmentation of the lens nucleus, which consists in the formation of tunnel access and corneal paracentesis, the introduction of viscoelastic, capsulorexis, hydrodissection, hydrodelineation, destruction of the lens nucleus with an energy of Nd-YAG laser with a wavelength of 1.44 μm, spend laser exposure of the nucleus initially along the edge of capsulorexis with the formation of a central fragment, the fragment is lifted with further laser exposure parallel to the EU ety move the lens fibers from the weakest of nuclear substances and the side of the aspiration fragment degradation products. Then, due to the weakening of the bonds between the fibers of the lens substance at the periphery from the capsulorexis zone after the initial exposure, the subsequent disintegration of the remaining part of the nucleus by laser radiation with a lower energy level, dilution and movement of the resulting fragments to the center of the surgical field for their final destruction and aspiration is easily achievable. It is most advantageous to produce this set of actions using a laser tip-manipulator equipped with a spatula-shaped element of the working part (RF patent No. 2341239). In this case, the working part of the laser tip-manipulator is positioned so as to orient the position of the spatula-shaped element from the side of finding nearby sensitive eye structures, for example, the edges of capsulorexis or the iris with a narrow pupil. Consequently, the diverging laser beam of the end part of the fiber will be shielded from the indicated side and partially reflected on the lens masses, allowing the laser tip-manipulator to work endocapsularly even beyond the edge of the capsulorexis without the risk of damage at the minimum necessary distance from each layer of the destroyed nucleus. This makes it possible to efficiently form the grooves of the fractures of the lens nucleus with relatively small diameters of capsulorexis, namely less than the diameter of the used intraocular lens, which is important for the prevention of secondary cataract in the postoperative period (B.E. Malyugin. Cataract surgery and intraocular correction of aphakia: achievements, problems and development prospects // Bulletin of Ophthalmology, 2006, No. 1, pp. 39-40). It seems that the factors of the initial impact not on the central, but on less dense tissues in the capsulorexis area allow not only to achieve, with lower energy costs, the allocation of the central fragment for its subsequent disintegration along the lens fibers with almost one and a half times lower energy level, but also to provide at the same time, the separation of the peripheral part of the nucleus to facilitate its fragmentation at the final stage.

The proposed technical solution is as follows.

The method of laser fragmentation of the lens nucleus consists in the formation of tunnel access and corneal paracentesis, the introduction of viscoelastic, capsulorexis, hydrodissection and hydrodelineation. The lens nucleus is destroyed by exposure to an Nd-YAG laser with a wavelength of 1.44 μm. Laser exposure is performed on the nucleus initially along the edge of the capsulorexis with the formation of one or more central fragments of a predominantly cylindrical shape. In this case, the working part of the laser tip-manipulator is positioned so as to orient the position of the spatula-shaped element from the side of finding nearby sensitive eye structures, for example, the edges of capsulorexis or the iris with a narrow pupil. Further, the obtained fragments are lifted by a laser tip-manipulator and destroyed from the side of their lateral surface parallel to the natural course of the lens fibers with a laser energy of 130-170 mJ. The remaining peripheral part of the nucleus with the interlaminar bonds weakened after the initial exposure is destroyed by sequentially directing the laser energy to the lens substance at several points. It is possible to introduce a spatula-shaped element of the laser tip-manipulator into the formed faults with simultaneous laser action directed both deep into the slit and coaxially along the lens fibers from the side of the opening fault wall. Then, by moving towards the spatula-shaped element with additional laser pulses, it is easy to separate the periphery of the nucleus into fragments and dilute them, followed by the final laser disintegration and aspiration.

The method is illustrated by clinical examples.

Example 1. Patient K., 74 years old.

Received complaints of decreased vision in the right eye.

Visual acuity of 0.08 with correction.

IOP = 21 mmHg

Keratometry: 42.85D ax 0 deg., 42.45D ax 90 deg.

Eye length 23.5 mm; no additional echo signals are detected.

Biomicroscopically, the cornea is transparent, the anterior chamber is of medium depth, diffuse opacification of the layers of the lens with a dark yellow hue.

Diagnosis: immature age-related cataract of the right eye. An operation was performed according to the proposed method of laser fragmentation of the lens nucleus with a maximum level of laser radiation energy of 130 mJ. An implanted elastic intraocular lens of the Biocryl model was implanted.

At discharge:

visual acuity 0.8 with sph correction - 0.5D = 1.0.

IOP = 22 mmHg

Keratometry: 42.8 D ax 0 deg., 42.4 D ax 90 deg.

Biomicroscopically, the cornea is transparent, the anterior chamber is deep, the moisture is clear, the IOL is in the capsule bag, in the correct position, the optic nerve disc is pale pink with clear contours on the fundus, angiosclerosis, without gross focal changes on the periphery.

Example 2. Patient G., 60 years old.

He received complaints of decreased vision as a result of a traffic accident with a traumatic brain injury and damage to the spleen and diaphragm several months ago. Moved to splenectomy.

Visual acuity of the left eye: the correct projection of light.

IOP = 23 mmHg

Keratometry: 42.8D ax 0 deg., 41.15D ax 90 deg.

Eye length 23.44 mm; no additional echo signals are detected.

Biomicroscopically, the cornea is transparent, the anterior chamber is medium

depths, diffuse opacification of all layers of the lens.

Diagnosis: Post-concussion cataract of the left eye.

An operation was performed according to the proposed method of laser fragmentation of the lens nucleus with a maximum level of laser radiation energy of 150 mJ. Implanted elastic intraocular lens model

Aqua Fold with an injector.

At discharge:

visual acuity of 0.7 with correction sph - 1,0D = 0,9.

IOP = 22 mmHg

Keratometry: 42.9D ax 0 deg., 41.0D ax 90 deg.

Biomicroscopically, the cornea is transparent, the anterior chamber is deep, the moisture is clear, the IOL is in the capsule bag, in the correct position, the optic nerve disc is pale pink with clear boundaries on the fundus, the reflex is preserved in the macular region, and there are no gross focal changes on the periphery.

Example 3. Patient B., 69 years old.

Received with complaints of decreased vision in the right eye.

Visual acuity: the correct projection of light.

IOP = 20 mmHg

Keratometry: 42.9D ax 0 deg., 44.6D ax 90 deg.

Eye length 23.77 mm; no additional echo signals are detected.

Biomicroscopically, the cornea is transparent, the anterior chamber is of medium depth, the rigid pupil is 3.5 mm in diameter at maximum mydriasis, pronounced pseudoexfoliation deposits on the anterior capsule of the lens, homogeneous opacification of all layers of the lens with a brownish tint.

Diagnosis: Mature age-related cataract of the right eye.

An operation was performed according to the proposed method of laser fragmentation of the lens nucleus with a maximum level of laser radiation energy of 170 mJ. An implanted elastic intraocular lens of the Aery Sof IQ model was implanted.

At discharge:

visual acuity of 0.5 with correction sph - 1,0D = 0.8.

IOP = 21 mmHg

Keratometry: 43.0 D ax 0 deg., 44.1 D ax 90 deg.

Biomicroscopically, the cornea is transparent, the anterior chamber is deep, the moisture is clear, the IOL in the capsule bag is in the correct position, the optic disk on the optic fundus is pale pink with clear contours, the reflex is smoothed in the macular region, angiosclerosis, and no gross focal changes on the periphery.

Thus, the given clinical examples confirm the high functional efficiency of the proposed method, since this technical solution creates the possibility of both exposure to the lens core along the natural fracture planes from the side of the least durable and, accordingly, less energy-intensive for fiber destruction, always at an optimum distance from the point of light scattering from the end of the fiber, as well as the protection of the stored structures, thereby providing a new effect of minimizing energy loads on the fabric and the eye during surgery.

Claims (3)

1. A method for laser fragmentation of the lens nucleus, which consists in forming tunnel access and corneal paracentesis, introducing viscoelastic, performing capsulorexis, destroying the lens nucleus with laser energy of an Nd-YAG laser with a wavelength of 1.44 μm, characterized in that they initially perform laser irradiation of the nucleus along the edge of capsulorexis with the formation of a central fragment, the fragment is lifted with further laser irradiation parallel to the natural course of the lens fibers from the side ie lasting nuclear matter and aspiration of debris. 2. The method according to claim 1, characterized in that the laser irradiation, lifting and formation of core fragments is carried out by a laser tip-manipulator equipped with a spatula-shaped element. 3. The method according to claims 1 and 2, characterized in that the levels of maximum laser radiation energy of 130-170 mJ are used during fragmentation.