SU1660698A1 - Myopia correction method - Google Patents

Abstract

The invention relates to medicine, namely eye microsurgery, and concerns refractive keratoplasty. The purpose of the invention is to increase the functional effect of the operation, reduce the time of rehabilitation of the patient, prevent transplant rejection and increase postoperative visual acuity. The method consists in generating a biolinse from the recipient's own corneal epithelial tissue by transplanting a concentric-optical zone of a ring-shaped graft with an inner diameter equal to the diameter of the generated biolinse and the thickness of the inner edge equal to the thickness of the biolinse edge. 1 il.

Description

This invention relates to medicine, namely to refractive keratoplasty.

The aim of the invention is to reduce postoperative complications and increase postoperative visual acuity.

The drawing shows a diagram of the operation.

To accomplish this goal, a biolinza is generated from the cornea's own epithelial tissue of the recipient by transplanting the concentric-optical zone of the allotransplant in the shape of a ring, the inner diameter of which is equal to the diameter of the generated lens, and the thickness of the inner edge is equal to the thickness of the lens edge.

The method is carried out as follows.

Immediately before the intervention, a ring-shaped graft is made with parallel anterior and posterior surfaces and a pointed outer edge — by turning it out of a frozen cornea disk using a sphere turning machine or by cutting

layer-by-layer disc of the cornea from the donor eye using a Barraker microkeratome, followed by dissecting the central opening in it with a trephine. After akinesia and retrobulbar anesthesia with a 2% solution of novocaine, bridle sutures are applied to the upper and lower rectus muscles of the eyes, the eyelids are fixed with blepharostat. Using a marker and an indifferent dye (solution of brilliant green or methylene blue), a mark in the form of a circumference demarcating its central optical zone with a diameter of 3.0-7.0 mm, concentric of which with a dosed trepan, exceeding 2.0-6.0 mm in diameter of the optical zone, cut the cornea to a depth of 0.15-0.2 mm The epithelium is removed to the center from the incision to the border of the optical zone by means of applications with a cotton swab moistened with a 3% dikain solution, followed by scraping the epithelium with a scraper. Then, at the level of the bottom of the incision, the cornea is stratified to the periphery using a round knife, forming a

ABOUT

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an interlayer interlayer pocket 1 with a width of 0.25-0.5 mm. The pre-assembled β-layer annular allograft 2 is applied with a stromal surface to the bowmen membrane of the decapitalized annular cornea section 3 of the recipient, the outer pointed edge of the graft is filled into the interlayer pocket and fixed with sutures. At the same time, the diameter of the graft's inner circumference is equal to the diameter of the optical corona of the recipient, and the diameter of the outer circumference exceeds the diameter of the concentric incision by 0.25-0.5 mm.

The mechanism of generating biolines from the corneal epithelium of the recipient is that the edge of the inner circle 4 of the Transplant, rising above the surface of the cornea along the border of the optical zone, thus forms the central bed, which for 1.5-2 months. after intervention, it is filled with epithelium (shaded in the drawing), proliferating and advancing into the bed area from the periphery of the recipient's cornea. By filling the bed, the epithelial tissue forms in the optical zone a negative lens 5, weakening the refraction of the cornea and the eye as a whole and correcting the myopia thus present. At the same time, the optical power of the epithelial lens that forms, and accordingly the refractive effect of the operation, depends on the thickness of the edge of the inner circumference of the transplanted ring-shaped allograft. Therefore, depending on the degree of myopia present, a transplant is transplanted with a given thickness of the edge of its inner circumference, the required value of which is determined by the following formula:

T-fr-YrMfF - P-P | 7

where T is the target value of the edge thickness of the inner circumference of the transplate:

r is the initial radius of curvature of the anterior surface of the cornea of the recipient;

P - the required radius of curvature of the anterior surface of the cornea of the recipient in the optical zone (radius of the anterior surface of the epithelial lens) after the operation;

and the diameter of the optical zone or the inner circumference of the graft.

PRI me R 1. Patient A, was admitted to the clinic with a diagnosis: high myopm of both eyes, mystic anisometry, partial amblyopia of the right eye. The patient was admitted for the surgical correction of myopia in the right eye in order to eliminate anisometropia. Upon enrolment

visual acuity of the right eye 0.01 sff - 21.0 diopters. 0.4; the left eye of 0.02 sf - 11.0 diopters. 1.0 Right eye: 180 ° M refractometry 23.0 diopters, 90 ° M 24.0 diopters: the average value of the initial refraction of the horn by the main meridians is 42.25 diopters, (, 86 mm), the required refraction of the cornea after the operation, determined by test contact correction, 34.0 diopters. (p 9.76 mm).

5 Produced surgical correction

myopia in the right eye of the proposed method. On the cornea of the right eye, a layered allograft machined on a sphere turning machine was transplanted

0 ring shape with the following parameters: outer diameter of 8.0 mm; diameter of the inner circle (a) 5.0 mm; the thickness of the edge of the inner circle (T), calculated by the formula with known magnitudes of g and n, was 0.09 mm.

Graft-fixing sutures are removed after 1 month. after operation. After 2 months after surgery, the graft is transparent; biomicroscopic in the optical zone

0 a negative lens is observed; visual acuity of 0.02 sf - 10.0 diopters. 0.5; refractometry 180 ° M 11.0 diopters ,, 90 ° M 11.5 diopters; the average value of corneal refraction over the main meridian5 is 34.6 diopters.

After 6 months after surgery, the graft remained transparent, the negative lens was retained in the optical zone; these visual acuity, refractometry and corneal refraction were unchanged. PRI me R 2, Patient I. was admitted to the hospital with a diagnosis of high myopia of the left eye; the right eye is healthy. The patient was admitted for the surgical correction of myopia in the left eye. When entering visual acuity of 0.02 with ff -14.0 diopters. 0.7. Refractometry: 180 ° M 16 diopters., 90 ° M 15.5 diopters. The average value of the initial corneal refraction is 45.5 diopters. (g - 7.3 mm);

0 required corneal refraction after surgery 33.0 diopters. (n 10.06 mm).

Surgical correction of myopia on the left eye was carried out using the proposed method. A layered allograft with the following parameters was fabricated with a microkeratome transplanted to the left eye with a microkeratome: outer diameter of 8.0 mm; inner circle diameter a) 5.0 mm; the thickness of the edge of the inner circle (T) 0,13 mm

After 2 months, after the operation, the graft is transparent, a negative lens in the optical zone of the cornea is formed; visual acuity of 0.6 sf + 0.75 diopters. 0.8; refractometry 180 ° Nm 1.5 diopters, 90 ° Nm 0.5 diopters; the average value of corneal refraction over the main meridians is 32.8 diopters.

In subsequent examinations after 4 and 6 months. after surgery, the state of the cornea and the graft, as well as the visual acuity and refractive effect of the operation, remain stable.

Thus, the invention has in comparison with the following known advantages. The formation in the optical zone of a corrective lens from one's own epithelial tissue allows one to avoid the light scattering phenomenon on the border of the adjacent surfaces of the graft and the cornea bed, which reduces postoperative visual acuity. In addition, the location of the donor transplant concentric with the optical zone of the cornea of the recipient eliminates the possibility of a negative impact

transplant transparency or epithelium growing under the transplant, on the functional effect of the operation.

The graft, which has a ring-shaped shape, reduces the degree of disturbance of hydrodynamic and metabolic processes due to the significantly smaller surface of the cornea of the recipient, which it covers, which reduces the likelihood of prolonged corneal edema of the recipient and the graft itself, as well as preventing disintegration and rejection of the graft in postoperative period.

Claims (1)

DETAILED DESCRIPTION A method for correcting myopia by transplanting a layered allograft onto the de-epithelized surface of the cornea, characterized in that, in order to reduce postoperative complications and improve postoperative visual acuity, the allograft is transplanted in a concentric-optical-optical ring.