RU2826851C1 - Method for intraoperative correction of induced astigmatism during keratoplasty - Google Patents

Abstract

FIELD: medicine; ophthalmology.

SUBSTANCE: invention can be used for intraoperative correction of induced astigmatism during keratoplasty. That is ensured by cutting out a donor corneal transplant (DCT). Corneal-scleral disc is placed in an artificial anterior chamber wherein an intraocular pressure close to normal is created using an irrigation system. Blade is used to make a keratotomy incision in a paracentral area of a donor cornea at distance of 2.0–2.4 mm from its center. Starting from the keratotomy incision, an intrastromal corneal tunnel (ICT) is formed concentrically to a limb with circumference of 360 degrees: inner diameter—4.0–4.8 mm, outer diameter—5.6–6.4 mm with pitch of 0.1 mm, depth based on residual stroma thickness of 150 mcm under ICT for implantation of an open ring with arc length of 359 degrees. Then, through trepanation of donor cornea with diameter of 8.0 mm is performed concentrically to formed ICT. Obtained DCT remains in the artificial anterior chamber until the recipient bed is prepared. Then the recipient’s bed is prepared. If deep anterior layer-by-layer keratoplasty is not possible, through trepanation with diameter of 8.0 mm is performed with the help of vacuum trephine to perform through keratoplasty. If the endothelial layer is preserved, a deep anterior layer-by-layer keratoplasty is performed, and surface layers of the recipient's cornea with diameter of 8.0 mm are removed. After the recipient’s bed is prepared, the DCT is fixed. Both through and deep anterior layer-by-layer keratoplasty for fixation of graft to recipient cornea is applied with interrupted submerged sutures. Then, an open polymethyl methacrylate ring is implanted into the formed ICT: arc length is 359 degrees, inner diameter is 4.2–5.0 mm, outer diameter is 5.4–6.2 mm, height is 150–350 mcm. Before implantation of the ring, a keratotomy incision is opened and an ICT with a spatula, ring is held by means of two forceps for tying and successively moved inside ICT. After implantation of 2/3 of the ring, a reverse Sinskey hook is used, with the help of which the ring is advanced further into the ICT and the ring rupture is placed at 30–40 angular degrees from the keratotomy incision. Submersible nodal incision is made on the keratotomy incision.

EFFECT: invention provides a gentle and safe intraoperative correction of induced astigmatism during keratoplasty with minimal traumatization, thereby reducing the number of postoperative complications, increasing the reliability of the operation, maintaining the optimal conditions for the reliable adaptation of the corneal graft, preserving the anatomical and topographic relationships in the eye, which ultimately enables to achieve optimal anatomical and functional results in the absence of a femto-lasik.

1 cl, 3 ex

Description

The invention relates to medicine, namely to ophthalmology, and is intended for intraoperative correction of induced astigmatism during keratoplasty.

The performance of penetrating and deep anterior lamellar keratoplasty is inextricably linked with the occurrence of induced astigmatism of varying degrees in 100% of cases.

High values of induced astigmatism are the cause of low visual acuity after keratoplasty and patient dissatisfaction with the postoperative result. According to various authors, astigmatism of 5.00 D or more is diagnosed after penetrating keratoplasty in 15-27% of patients. Today, there is a wide range of different methods for correcting postkeratoplastic ametropia: various types of keratotomy, wedge resection, implantation of toric intraocular lenses, refractive surgeries PRK and LASIK, implantation of intrastromal segments into a corneal transplant, etc.

The closest analogue is “Method for performing keratoplasty (options)”.

The method consists in the fact that for correction of induced postkeratoplastic astigmatism and high myopia during penetrating and deep anterior lamellar keratoplasty on the donor cornea using a femtosecond laser, an intrastromal ring tunnel is formed concentrically to the limbus at a depth of ¾ of the thickness, choosing an internal diameter from 3 mm to 9 mm with a step of 0.25 mm, and one incision above the tunnel for entering it. Then, using a femtosecond laser, a penetrating incision is made in the donor cornea concentrically to the limbus, choosing a diameter from 6 mm to 9 mm with a step of 0.25 mm, thus forming a transplant. An open intrastromal ring is implanted into the formed transplant between the separated layers, choosing its internal diameter from 3 mm to 6 mm with a step of 0.25 mm, and a thickness from 100 µm to 400 µm with a step of 0.25 mm (Patent of the Russian Federation for Invention No. 2589633).

The disadvantages of this method of operation include the following:

Firstly, using the specified method, a femtolaser installation is required.

Secondly, working on a femtolaser installation requires additional professional training of specialists and advanced training.

Thirdly, when using a femtolaser system, the cost of surgical intervention increases due to the cost of consumables.

The objective of the invention is to create a method for intraoperative correction of induced astigmatism during keratoplasty, which allows improving visual functions and restoring binocular vision, as well as performing this type of surgical intervention in all operating rooms not equipped with a femtolaser installation, and reducing costs.

The technical result of the invention is to ensure gentle and safe intraoperative correction of induced astigmatism during keratoplasty with minimal trauma, thereby reducing the number of postoperative complications, increasing the reliability of the operation, maintaining optimal conditions for reliable adaptation of the corneal transplant, preserving the anatomical and topographic relationships in the eye, which ultimately allows achieving optimal anatomical and functional results in the absence of a femtolaser installation.

The proposed method is implemented as follows.

The operation is performed under local anesthesia with intravenous administration of pain-relieving sedatives. The surgical field is treated and an eyelid retractor is installed.

The first stage involves cutting out the donor corneal transplant (DCT). The corneoscleral disc is placed in the artificial anterior chamber, in which the intraocular pressure close to normal is created using an irrigation system. Using a blade, a keratotomy incision is made in the paracentral zone of the donor cornea at a distance of 2.0-2.4 mm from the center, and, starting from the incision, an intrastromal corneal tunnel (ICT) is formed with a dissecting tool concentrically to the limbus with a circumference of 360 degrees: internal diameter - 4.0-4.8 mm, external diameter - 5.6-6.4 mm with a step of 0.1 mm, depth based on the calculation of the residual stromal thickness of 150 μm under the ICT for implantation of an open ring with an arc length of 359 degrees. Afterwards, a penetrating trepanation of the donor cornea with a diameter of 8.0 mm is performed concentrically to the formed IRT. The resulting DTR remains in the artificial anterior chamber until the next stage.

The preparation of the recipient's cornea for transplantation largely depends on the severity of the corneal stromal lesion and the integrity of the endothelial layer. If deep anterior lamellar keratoplasty is not possible, a penetrating trephine with a diameter of 8.0 mm is performed using a vacuum trephine to perform penetrating keratoplasty. If the endothelial layer is intact, deep anterior lamellar keratoplasty is performed, removing the superficial layers of the recipient's cornea with a diameter of 8.0 mm.

After the recipient bed is prepared, the DTR fixation begins. In both penetrating and deep anterior lamellar keratoplasty, 16 interrupted immersion sutures of 10/0 nylon are applied to fix the graft to the recipient's cornea. The next step is the implantation of an open ring into the formed IRT. The open ring manufactured by NEP Eye Microsurgery LLC is made of polymethyl methacrylate: arc length is 359 degrees, internal diameter is 4.2-5.0 mm, external diameter is 5.4-6.2 mm, height is 150-350 μm. Before the ring implantation, the keratotomy incision and IRT are opened with a spatula, the ring is held with two tying tweezers and sequentially advanced inside the IRT. After implantation of 2/3 of the ring, a reverse Sinsky hook is used to advance the ring further into the ITR and position the ring break at 30-40 angular degrees from the keratotomy incision.

A 10/0 nylon immersion interrupted suture is placed on the keratotomy incision.

The advantages of the proposed method are as follows:

- Thanks to the claimed method, it is possible to perform intraoperative correction of induced astigmatism during keratoplasty in a highly effective and safe way;

- Thanks to the use of the declared method, the risks of postoperative complications are reduced;

- Thanks to the implementation of the proposed method of intraoperative correction of induced astigmatism in one stage, minimal trauma is achieved, the number of postoperative complications is reduced and the reliability of the operation is increased;

- To implement the claimed method, a femtolaser installation is not required.

The method is characterized by the following clinical examples:

Example 1. Patient K., 33 years old. Diagnosis OS: Keratoconus stage IV. Visual acuity OS: 0.01 not corrected.

Deep anterior lamellar keratoplasty was performed according to the claimed method. A keratotomy incision was made in the donor cornea at a distance of 2.0 from the center, an IRT with an internal diameter of 4.0 mm and an external diameter of 5.6 mm was formed. A penetrating trepanation of the donor cornea with a diameter of 8.0 mm was performed and Descemet's membrane with endothelium was removed. The transplant was fixed to the recipient's cornea with 16 interrupted sutures, after which an open ring of 359 angular degrees with an internal diameter of 4.2 mm, an external diameter of 5.4 mm, a height of 350 μm, and a depth of 400 μm was implanted into the formed IRT, while the ring rupture was located at 30 angular degrees from the keratotomy incision. An interrupted immersion suture (10/0 nylon) was applied to the keratotomy incision. No complications were observed during the operation or in the postoperative period. Biomicroscopically and according to OCT of the anterior segment of the eye - complete adaptation of the corneal transplant, correct position of the ring in the corneal transplant. On the first day after the operation, visual acuity: 0.3 cyl -1.5 ах 70° = 0.5.

One month after the operation, visual acuity: 0.5 cyl -1.0 ax 90° = 0.75.

Example 2. Patient V., 55 years old. Diagnosis OS: Posttraumatic corneal scar. Visual acuity OS: 0.02 not corrected.

Penetrating keratoplasty was performed according to the claimed method, the keratotomy incision was made at a distance of 2.15 from the center, an IRT with an internal diameter of 4.3 mm and an external diameter of 5.9 mm was formed. A penetrating trepanation of the donor cornea with a diameter of 8.0 mm was performed. The transplant was fixed to the recipient's cornea with 16 interrupted sutures. An open ring of 359 angular degrees with an internal diameter of 4.5 mm, an external diameter of 5.7 mm, a height of 250 μm, and a depth of 450 μm was implanted into the formed IRT, while the ring rupture was located at 35 angular degrees from the keratotomy incision. No complications were observed during the operation and in the postoperative period. Biomicroscopically and according to OCT data of the anterior segment of the eye - complete adaptation of the corneal transplant, correct position of the ring in the corneal transplant. On the first day after the operation, visual acuity: 0.3 cyl +2.0 ах 111° = 0.6.

One month after the operation, visual acuity: 0.55 cyl -0.5 ax 90° = 0.8.

Example 3. Patient S., 40 years old. Diagnosis OD: Keratoconus stage IV. Visual acuity OD: 0.01 not corrected.

Penetrating keratoplasty was performed according to the claimed method, the keratotomy incision was made at a distance of 2.4 from the center, an IRT with an internal diameter of 4.8 mm and an external diameter of 6.4 mm was formed. A penetrating trepanation of the donor cornea with a diameter of 8.0 mm was performed. The transplant was fixed to the recipient's cornea with 16 interrupted sutures. An open ring of 359 angular degrees with an internal diameter of 5.0 mm, an external diameter of 6.2 mm, a height of 150 μm, and a depth of 450 μm was implanted into the formed IRT, while the ring rupture was located at 40 angular degrees from the keratotomy incision. No complications were observed during the operation and in the postoperative period. Biomicroscopically and according to OCT data of the anterior segment of the eye - complete adaptation of the corneal transplant, correct position of the ring in the corneal transplant. On the first day after the operation, visual acuity: 0.3 cyl +1.5 ах 110° = 0.4.

One month after the operation, visual acuity: 0.6 cyl -0.5 ax 90° = 0.7.

Claims (1)

A method for intraoperative correction of induced astigmatism during keratoplasty, including the formation of an intrastromal corneal tunnel (ICST), cutting out a donor corneal graft (DCT), preparing the recipient bed, fixing the DCT to the recipient cornea, and implanting an open ring made of polymethyl methacrylate, characterized in that the DCT is placed in an artificial anterior chamber in which normal intraocular pressure is created; in the paracentral zone of the DTR at a distance of 2.0-2.4 mm from its center, a keratotomy incision is made with a blade and from the keratotomy incision, an IRT with a 360-degree circumference is formed with a dissecting tool: with an internal diameter of 4.0-4.8 mm, an external diameter of 5.6-6.4 mm, a depth based on the residual stromal thickness of 150 μm under the IRT for implantation of an open ring with an arc length of 359 degrees, a height of 150-350 μm with a step of 50 μm, with an internal diameter of 4.2-5.0 mm, an external diameter of 5.4-6.2 mm, a through trepanation of the donor cornea with a diameter of 8.0 mm is performed concentrically to the formed IRT, the DTR obtained in this way is left in the artificial anterior chamber until the recipient bed is prepared, which is performed as follows: when performing deep anterior lamellar keratoplasty, a non-penetrating trepanation of the recipient's cornea with a diameter of 8.0 mm using a vacuum trepan at a residual thickness of 100 μm and remove the stroma up to the Descemet's membrane, while the Descemet's membrane with the endothelium is removed with the DTR using tweezers; when performing penetrating keratoplasty, a penetrating trepanation of the recipient's cornea with a diameter of 8.0 mm is performed using a vacuum trepan; After preparing the recipient bed, they begin fixing the DTR, for which they apply interrupted immersion sutures, capturing the DTR and the recipient's cornea, after fixing the DTR and the recipient's cornea, they implant an open ring with an arc length of 359 degrees into the IRT using two tying tweezers, after implanting 2/3 of the ring, they use a reverse Sinsky hook, with which they advance the ring further into the IRT, placing the ring break at 30-40 angular degrees from the keratotomy incision, the operation is completed by applying an interrupted suture to the keratotomy incision.