METHOD FOR INTRAOPERATIVE CORRECTION OF INDUCED ASTIGMATISM DURING KERATOPLASTY Russian patent published in 2024 - IPC A61F9/07 A61F2/14 

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