RU2118144C1 - Method and implant for surgically correcting high-degree myopia - Google Patents

Abstract

FIELD: OPHTHALMOLOGY. SUBSTANCE: invention relates to refraction surgery and consists in that, first, partial keratectomy with stem is performed and then ring-like implant with convex upper surface is laid intrastromally. Thickness of the ring in its center is 0.15-0.3 mm. Ratio of maximal diameters of outer and inner rings to minimal ones ranges from 0.15 to 1.05. Cornea flap is brought into its original position. EFFECT: increased refraction. 2 cl

Description

 The invention relates to medicine, more specifically to ophthalmology, and can be used in the surgical correction of high myopia.

 A known method of surgical correction of high myopia, including a circular tunnel interlayer ("ring") keratoplasty (G.A. Uldanov, L.D. Robman, Yu.A. Shusterov. Alma-Ata, USSR. 2 international symposium on refractive surgery, of IOL implantation and complex treatment of optic atrophy (Moscow, September 16-18, 1991, Abstracts, p. 65), by introducing into the cornea a ribbon-shaped interlayer implant along the circumference surrounding the optical zone of the cornea.

However, ring tunnel keratoplasty has several disadvantages:
- reduction of refractive effect in the long term observation,
- trauma to the corneal tissue when tunneling and conducting a ribbon-like interlayer implant,
- long term rehabilitation of patients in the postoperative period,
- the complexity of the surgical intervention.

 The objective of the invention is to provide a method for surgical correction of high myopia with a thin and flat cornea, as well as with a "loose" and "thick" conjunctiva in order to obtain a high, persistent refractive effect, shorten the rehabilitation of patients, reduce the degree of trauma to corneal tissue at the time of surgery simplification of surgical intervention.

 The technical result is achieved by the fact that after performing a keratectomy “on the leg”, a ring-shaped intrastromal implant is placed on the stromal bed formed, then the superficial corneal flap returns to its original position.

 The intrastromal ring-shaped implant for the implementation of the method is made in the form of a ring with a flat lower surface and a convex upper surface with a ring thickness in the center of 0.15 to 0.3 mm and a ratio of the maximum diameters of the outer and inner rings to the minimum diameters of the outer and inner rings in the range of 1 02 - 1.05.

 The ring-shaped intrastromal implant is made of elastic, optically transparent, collagen intact to eye tissues.

 To achieve the maximum refractive effect, the thickness of the ring-shaped intrastromal implant in the center should lie in the range 0.15 - 0.3 mm, because with a smaller or greater thickness, it is impossible to obtain the desired high refractive effect. The ratio of the minimum external and internal diameters should be at least 1.02, because otherwise the ring falls into the central optical zone. Also, the ratio of the maximum external and internal diameters should be no more than 1.05, because otherwise, a high functional result will not be achieved.

Our proposed method of surgical correction of high myopia with the introduction of a ring-shaped intrastromal implant into the cornea has the following advantages:
- high precision dosed refractive effect,
- persistent refractive effect,
- the least trauma to the corneal tissue, because partial keratectomy is performed within only 2-3 cell layers,
- reduction of the rehabilitation period of patients,
- the availability of surgery.

 The method is as follows: the patient under local anesthesia undergoes partial keratectomy "on the leg" with the help of a Heron microkeratome, a ring-shaped intrastromal implant is placed on the formed stromal bed and then the surface corneal flap is returned to its original position. The operation ends with the application of nodal sutures and the introduction of an antibiotic solution under the conjunctiva.

 Example: Patient A., 35 years old.

 Diagnosis: High myopia, anisometropia.

Preoperative examination data:
Visual acuity OD - 0.02 sph - 17.0 cyl - 0.5 ax 0 - 0.4 n / k
Visual acuity OS - 0.03 sph - 9.0 cyl - 0.5 ax 5 - 0.7 n / k
Keratometry:
OD: 43.25; 42.80
OS: 43.25; 42.73
Pachymetry in the center of OD - 468 microns, OS - 471 microns
Eye length OD - 29.18 mm, OS - 26.93 mm
ROSE OD - 0.5 OS - 0.7
The patient underwent implantation of a ring-shaped intrastromal implant in both eyes using the present invention. On OD, the patient was implanted with a 0.3 mm thick ring in the center, and the ratio of external and internal diameters is 1.02. On the OS, the patient was implanted with a ring with a thickness of 0.15 mm in the center, and the ratio of external and internal diameters was 1.05.

Examination data 10 days after surgery:
Visual acuity OD - 0.2 sph - 2.0 cyl - 0.5 ax 0 - 0.4 - 0.5 n / k
Visual acuity OS - 0.6 cyl - 0.5 ax 6 - 0.7 n / k
Keratometry:
OD 58.22; 57.93
OS 51.31; 51.87
During biomicroscopy: OU - calm, the cornea is transparent, shiny, the surface flap is adapted, there is no edema, the ring-shaped intrastromal implant is in the correct position, deep-lying media are transparent.

 In total, according to the proposed method, 33 patients and 57 eyes were operated on.

Claims (1)

 \ \ \ 1 1. A method for the correction of high myopia, including annular keratoplasty, characterized in that they produce partial keratectomy "on the leg", an annular intrastromal implant is placed, then the corneal flap is returned to its original position. \\\ 2 2. An implant for the correction of high myopia, made with a flat lower surface, characterized in that it is made in the form of a ring with a convex upper surface, while the thickness of the ring in the center lies in the range from 0.15 to 0.3 mm, and the ratio of the maximum diameters of the rings, external and internal, to the minimum diameters, external and internal, lies in the range from 1.02 to 1.05.