RU2222299C1 - Method for repeated operation of subfragmentary photokeratectomy after radial keratotomy carried out earlier - Google Patents

Abstract

FIELD: medicine, ophthalmology. SUBSTANCE: one should isolate margins of corneal lamellar fragment and separate it. Photokeratoablation and reapplication of corneal fragment is conducted. Moreover, one should find and separate these margins alternately in all segments developed with radial keratotomic scars by not taking the latter. One should separate the fragment in each segment, as well, in direction being from margin towards center. Separation of scars area is carried out alternately in direction from the center of optic area towards corneal fragment's margin. EFFECT: higher efficiency of repeated operation. 4 dwg

Description

 The invention relates to ophthalmology, in particular to excimer laser refractive surgery, and can be used to correct residual ametropia after previous operations: radial keratotomy and laser keratomileusis.

 The primary operation of radial keratotomy in the correction of myopia and myopic astigmatism is performed as follows. In the central part of the cornea, an area of 3 mm in diameter is noted. Then, with a special screed moistened with dye, mark the location of the radial cuts in an amount corresponding to the magnitude of myopia. The cut radii from the center to the periphery of the diamond blade produce incisions in the thickness of the cornea to a depth of 80-90% of its thickness. In this case, the previously noted central optical zone is not affected. Subsequently, the incision is healed by ordinary scarring. The mechanism of action of the operation is that the rigidity of the corneal framework decreases, intraocular pressure slightly stretches the tissue in the central zone due to greater stretching in the middle part, the radius of curvature of the cornea increases, the optical power of the cornea decreases, the focal region of refraction of the rays entering the eyeball is shifted to the retina, increased visual acuity.

 However, over time, the development of residual myopia, inverse astigmatism, or progressive hyperopia may occur. In such conditions, there is a need for repeated corrective operations: repeated radial keratototomy (which is not always possible) or laser photorefractive operations.

 The primary operation of laser keratomileusis is as follows. In the cornea of the eye, a surface lamellar flap with a thickness of 130-180 μm and a diameter of 8 to 9 mm is cut out with a microkeratome, the flap is left on the bridge, turned up and one or more varieties of photoablation are performed on the surface of the stromal bed in accordance with the operation algorithm. Then the corneal flap is laid in its original place, and it is fixed in the future due to the surface epithelization of the edges of the slice, the formation of fibrous inflammatory tissue in the interface and pressing the lamellar flap with eyelid strength. However, even with repeated operations of the type described above, in the eyes with a previously performed keratotomy, regression of myopia, the formation of induced astigmatism and a hypereffect are possible.

 That is, in about 10-15% of cases, even after two of the above refractive surgeries, the third is possible, consisting in the detachment of the lamellar flap containing radial corneal scars. Such a task is not easy, and therefore there is a general opinion that it is better to perform it by re-cutting with a microkeratome to a similar or greater depth. The danger of re-peeling the flap is that the scars are very tightly fixed to each other and an attempt to peel the surface flap easily leads to its fragmentation and various kinds of damage. At the same time, re-cutting with a microkeratome is undesirable due to the possibility of new complications.

 A known method of forming a lamellar flap of the cornea with laser keratomileusis after previously performed radial keratotomy. After performing a lamellar cut with a microkeratome with the formation of a vertical jumper, Sinsky initially checks the flap around the entire circumference of the flap for tearing the flap in the keratotomy scar area. Then the hook is placed horizontally in the lower part of the flap and lift the lower part up, gradually moving to the upper parts of the flap, it is turned up without using tweezers. After the photoablation, the flap is repositioned and a bandage contact lens must be applied (MS Chung, JS Pepose, ЕЕ Manche. Management of corneal flap in laser in situ keratomileusis after previous radial keratectomy. K Am J Ophthalmol, 2001. - V.132. - August . - P.252-253).

 The disadvantages of this method include: the inability to use the proposed methods when re-separating the corneal flap with tight fixation to the bed with keratotomy scars, the inability to perform the procedure without complications with the previously fragmented corneal flap during the primary lamellar section, the need to use a bandage contact lens.

 Close to the claimed method is a method of raising the lamellar flap of the cornea after laser keratomileusis, which is performed in stages in the following sequence. The center of the cornea is marked with dye when the patient is looking at the fixing mark of the microscope. The cornea is labeled with an 8-ray keratotomy marker using a pink Bengal dye. Using a curved hook, Sinsky finds the edge of the corneal flap along the presented line in the area of 45 degrees to the temple and destroys the fixing tissue. MacPherson-type forceps without forceps grab, separate and and lift the flap. Stack it with its back surface up in the conjunctival region. With a medical sponge, the epithelium is pushed back along the edge of the slice. In a standard way, photo keratoablation is performed. The flap is repaired by cannula, keratotomy marking is used as a direction for the correct laying of the flap. After smoothing the flap is expected for 4-5 minutes. A plastic nameplate is placed on the eye (DS. Durrie, AA. Aziz Lift-flap retreatment after laser in situ keratomileusis. || J Refract Surg, 1999. - V. 15. - 3. - P.150-153).

 However, if the operation of laser keratomileusis is performed after radial keratotomy, repeated flap raising using the described method can be performed only up to 2 weeks after the operation. In other cases, the repeated lamellar section remains the method of choice, which increases the risk of complications.

 Closest to the claimed is a method of treating residual myopia after radial keratotomy is the following method. A microkeratome conducts a lamellar section of the cornea, including keratotomy scars, while forming a jumper (leg). The lamellar flap is turned upside down with a spatula. Then laser keratoablation of the stroma is carried out, and before reposition of the flap, excised keratotomy scars of the epithelium are excised along the edge. In this case, the operation also ends with the application of a contact lens for the cornea.

 The disadvantages of this method include: the inability to use the proposed methods with tight fixation by keratotomy scars of the initially cut lamellar flap, as well as the use of contact lenses (patent RU 2147425 from pr. From 09.10.1999, MKI A 61 F 9/008 from 04.20.2000. BI eleven).

 The objective of the invention is to improve the technique of raising the corneal flap during laser keratomileusis surgery in the eyes with keratotomy scars after radial keratotomy.

 The essence of the invention lies in the fact that the selection of the edges of the corneal flap is carried out alternately in the segments formed by radial scars, without affecting them, and the flap is separated from the center of the optical zone towards the periphery.

The technical result obtained by the implementation of the proposed method is expressed in the following:
- maintaining the integrity of the corneal valve along keratotomy scars;
- correction of residual ametropia and partial regression after keratotomy and the primary operation of laser keratomileusis;
- reducing the morbidity of the valve and improving its adhesive properties;
- eliminating the need for intraoperative contact lenses for subsequent compression of the corneal flap.

 The method is as follows. After drip anesthesia of the cornea and conjunctiva, the eyelids are immobilized with blepharostat. Then, using a thin spatula with a bent end, the edge of the corneal flap in all segments formed by radial keratotomy scars is found by the method of sliding movements. In all these found points, subglottal passages are created to a depth of 1-2 mm. The double-edged end of the spatula alternately enter these passages and cut the epithelial layer while simultaneously raising the flap edge by 1-2 mm throughout all segments, excluding the scar area (Fig. 1). A thin round spatula separates the corneal flap in each in the area of each segment to the center of the cornea, without touching the scar zone (figure 2). With the same spatula, in the direction from the optical center of the cornea, a flap in the projection of corneal keratotomy scars is alternately separated (Fig. 3). When the flap is completely immobilized, it is raised and, folding in half with the inner surfaces to each other, positioned on the outside of the limb. Stroma is ablated with an excimer laser. They clean the ingrown epithelium, etc. The flap is repaired, orienting along the scars (figure 4). The underlap space is washed with isotonic solution and the flap is adapted by known methods. Remove the eyelash extender. Steroidal or non-steroidal anti-inflammatory drugs and an antibiotic are instilled into the conjunctival cavity.

 Example. 1. Patient Ch., 46 years old, was operated on by the method of radial keratotomy 10 years ago for moderate myopia. 10 radial incisions were made. The result of the operation was effective for 3 years. In subsequent years, progressive hyperopia developed. On examination, clinical refraction of the left eye: sphere +6.0 diopters, cylinder +0.75 diopters, axis 150 degrees. Visual acuity without correction 0.05, with correction 0.8. The thickness of the cornea in the center is 546 microns. Diagnosis: condition after radial keratotomy, progressive hyperopia. In order to correct residual hyperopia, laser keratomileusis was performed according to the algorithm: sphere +6.0 diopters. The keratoablation depth is 65 microns, the thickness of the corneal flap is 160 microns. 9 months after the second operation, regression of the refractive result was noted. Visual acuity without correction of 0.15, with the correction of a spherical lens +4.0 diopters - is 0.7. The patient underwent a repeat operation of sublaptic photokeratoablation according to the proposed method. 6 months after this operation, refraction: sphere +0.75 diopters, cylinder -0.75 diopters, axis 30 degrees. Visual acuity without correction of 0.5, with correction of +0.5 diopters - equal to 0.7. Achieved a positive maximum possible result. No complications noted.

 Example 2. Patient A., 48 years old, was operated on by the method of radial keratotomy 12 years ago for moderate myopia. 8 incisions were made and emmetropia was achieved. In the remote period after surgery, progressive hyperopia developed. At the time of inspection, the refraction of the right eye: sphere +5.0 diopters, cylinder -2.5 diopters, axis 95 degrees. Visual acuity without correction 0.2, with correction points 0.6. The thickness of the cornea in the center is 516 microns. Diagnosis: condition after radial keratotomy, mixed astigmatism. In order to correct ametropia, laser keratomiliasis was performed according to refraction data sphere +5.0 diopters, ablation depth 134 μm. The thickness of the corneal flap is 130 microns. 3 months after the operation, regression of hyperopia was noted. Visual acuity without correction 0.3, with correction sphere +2.0 diopters, cylinder -1.0 diopters - 0.6. The patient underwent a repeat operation of sublaptic photokeratoablation according to the proposed method. 5 months after this operation, refraction: sphere -0.75 diopters, cylinder -0.25 diopters, axis 80. Visual acuity without correction 0.6. The maximum optical result was achieved without complications from the corneal flap.

 Captions to the drawings.

 FIG. 1-4. In the diagram of figure 1 are indicated: 1 - cornea; 2 - the estimated line of the previously performed lamellar slice; 3 - keratotomy scar. In all the figures, the arrows indicate the direction of movement of the instruments when peeling the lamellar flap of the cornea (see explanation in the text).

Claims (1)

The method of re-operation of a sublaptic photokeratectomy after a previously performed radial keratotomy, which consists in isolating the edges of the lamellar flap of the cornea, its separation, photo-keratoablation and re-laying of the corneal flap, characterized in that the search for and separation of the edges of the lamellar flap is done with all the redo segments without affecting the latter, the flap is also produced in each individual segment in the direction from the edge to the center, and the department the scar zone is carried out alternately in the direction from the center of the optical zone to the edge of the corneal flap.

Images